Resize images

Add image resizing parameters to a GetObject request to resize images on the fly.

Scenarios

Web design: Adapt images for different screen sizes and resolutions in web and mobile applications.
Social media: Convert user-uploaded images to standard preview dimensions.
Image recognition and analysis: Scale images to improve processing efficiency in computer vision and machine learning pipelines.

Limits

Limit	Item	Description
Source image limits	Image format	The source image must be in JPG, PNG, BMP, GIF, WebP, TIFF, or HEIC format.
	File size	The source image cannot exceed 20 MB. To increase this limit, submit a request in Quota Center.
	Width and height	The width or height of the source image cannot exceed 30,000 px, and its total pixels cannot exceed 250 million px. Note For animated images, such as GIFs, total pixels are calculated as `width × height × number of frames`. For static images, such as PNGs, total pixels are `width × height`.
Scaled image limits	Image scaling	A scaled image's width or height cannot exceed 16,384 px, and its total pixels cannot exceed 16,777,216 px.

Procedure

Append ?x-oss-process=image/resize,parameter_value to an image URL. OSS processes the image in real time and returns the result. image/resize specifies a resize operation, where parameter is a supported resizing parameter and value is its corresponding value. All available parameters are listed in the Parameters. You can combine multiple parameters.

For public-read images, append parameters directly to the URL. For private images, generate a signed URL using an SDK or call an API operation.

Public-read images

Add ?x-oss-process=image/resize,parameter_value to a public-read image URL. Replace parameter_value with your required parameters and values.

Original image URL	Image URL with resizing parameters
https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,p_50

Private images

Use an OSS SDK to generate a signed URL that includes image resizing parameters. The following examples generate a signed URL with ?x-oss-process=image/resize,parameter_value for a private image:

Java

package com.aliyun.oss.demo;
import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.GeneratePresignedUrlRequest;
import java.net.URL;
import java.util.Date;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // This example uses the endpoint of the China (Hangzhou) region. Replace the value with the actual endpoint.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain credentials from environment variables. Ensure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET variables are configured before running the code.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the bucket name. Example: examplebucket.
        String bucketName = "examplebucket";
        // Specify the object's full path. If the object is not in the bucket's root directory, you must include its full path, such as exampledir/exampleobject.png.
        String objectName = "exampledir/exampleobject.png";
        // Specify the region ID where the bucket is located. For example, the region ID for China (Hangzhou) is cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // Call the shutdown method to release resources when the OSSClient instance is no longer needed.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Resize the image. Replace parameter_value with a specific parameter and value. For example, p_50 proportionally scales the image to 50% of its original size.
            String style = "image/resize,parameter_value";
            // Specify the expiration time of the signed URL. In this example, the signed URL expires in 3,600 seconds.
            Date expiration = new Date(new Date().getTime() + 3600 );
            GeneratePresignedUrlRequest req = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.GET);
            req.setExpiration(expiration);
            req.setProcess(style);
            URL signedUrl = ossClient.generatePresignedUrl(req);
            System.out.println(signedUrl);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

Python

# -*- coding: utf-8 -*-
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

# Obtain credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())

# Specify the bucket name.
bucket = 'examplebucket'

# Specify the endpoint of the region where the bucket is located. This example uses the China (Hangzhou) region.
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'

# Specify the region ID.
region = 'cn-hangzhou'
bucket = oss2.Bucket(auth, endpoint, bucket, region=region)

# Specify the name of the source image. If the image is not in the root directory of the bucket, include the full path, such as exampledir/exampleobject.jpg.
key = 'exampledir/exampleobject.png'

# Specify the expiration time in seconds.
expire_time = 3600

# Resize the image. Replace parameter_value with a specific parameter and value. For example, p_50 proportionally scales the image to 50% of its original size.
image_process = 'image/resize,parameter_value'

# Generate a signed URL that includes image processing parameters.
url = bucket.sign_url('GET', key, expire_time, params={'x-oss-process': image_process}, slash_safe=True)

# Print the signed URL.
print(url)

PHP

<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\Credentials\EnvironmentVariableCredentialsProvider;
use OSS\OssClient;

// Obtain credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
$provider = new EnvironmentVariableCredentialsProvider();
// Set $endpoint to your bucket's region endpoint. For example, for a bucket in the China (Hangzhou) region, use https://oss-cn-hangzhou.aliyuncs.com.
$endpoint = "yourEndpoint";
// Specify the bucket name. Example: examplebucket.
$bucket= "examplebucket";
// Specify the full path of the object, such as exampledir/exampleobject.jpg. The full path cannot contain the bucket name.
$object = "exampledir/exampleobject.jpg";

$config = array(
        "provider" => $provider,
        "endpoint" => $endpoint,
        "signatureVersion" => OssClient::OSS_SIGNATURE_VERSION_V4,
        "region"=> "cn-hangzhou"
    );
    $ossClient = new OssClient($config);

// Generate a signed URL with image processing parameters. The URL is valid for 3,600 seconds and can be directly accessed in a browser.
$timeout = 3600;

$options = array(
    // Resize the image. Replace parameter_value with a specific parameter and value. For example, p_50 proportionally scales the image to 50% of its original size.
    OssClient::OSS_PROCESS => "image/resize,parameter_value");

$signedUrl = $ossClient->signUrl($bucket, $object, $timeout, "GET", $options);
print("signed url: \n" . $signedUrl);

Go

package main

import (
	"fmt"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
	fmt.Println("Error:", err)
	os.Exit(-1)
}

func main() {
	// Obtain credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Create an OSSClient instance.
	// Set yourEndpoint to the endpoint for your bucket's region. This example uses https://oss-cn-hangzhou.aliyuncs.com for the China (Hangzhou) region. Replace it with your actual endpoint.
	// Set yourRegion to the region where your bucket is located. This example uses cn-hangzhou for the China (Hangzhou) region. Replace it with your actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Set the signature version.
	clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
	client, err := oss.New("yourEndpoint", "", "", clientOptions...)
	if err != nil {
		HandleError(err)
	}

	// Specify the bucket name.
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}
	// Specify the image's full path. If the image is not in the bucket's root directory, include the full path (e.g., exampledir/exampleobject.png).
	ossImageName := "exampledir/exampleobject.png"
	// Generate a signed URL that is valid for 3,600 seconds. The maximum validity period is 32,400 seconds.
	// Resize the image. Replace parameter_value with a specific parameter and value. For example, p_50 proportionally scales the image to 50% of its original size.
	signedURL, err := bucket.SignURL(ossImageName, oss.HTTPGet, 3600, oss.Process("image/resize,parameter_value"))
	if err != nil {
		HandleError(err)
	} else {
		fmt.Println(signedURL)
	}
}

The following is an example of a generated signed URL:

https://examplebucket.oss-cn-hangzhou.aliyuncs.com/exampledir/exampleobject.png?x-oss-process=image%2Fresize%2Cp_50&x-oss-date=20241111T113707Z&x-oss-expires=3600&x-oss-signature-version=OSS4-HMAC-SHA256&x-oss-credential=LTAI********************%2F20241111%2Fcn-hangzhou%2Foss%2Faliyun_v4_request&x-oss-signature=6fd07a2ba50bf6891474dc56aed976b556b6fbcd901cfd01bcde5399bf4802cb

Additional SDK examples are available in the SDK reference.

Parameters

Operation: resize

Proportional scaling

The p parameter scales an image by a percentage of its original size.

Parameter

Description

Value

The scaling factor as a percentage.

An integer in the range [1, 1000].

A value less than 100 scales the image down, and a value greater than 100 scales it up.

Note

Animated images do not support this proportional scaling.

Scaling by width and height

Use the w and h parameters to specify the width and height, and the m parameter to control the scaling mode. To control the longest or shortest side, use the l or s parameter. To allow upscaling, set the parameter limit to 0.

Parameter	Description	Value
w	Specifies the width of the output image, in pixels.	[1,16384]
h	Specifies the height of the output image, in pixels.	[1,16384]
m	Specifies the scaling mode.	lfit (default value): Proportionally scales the image to fit within the specified width and height, and returns the largest possible image. mfit: Scales the image proportionally to cover the area specified by the width and height. If the image's aspect ratio differs from the target, the image is not cropped, and one output dimension may be larger than specified. fill: Scales the image proportionally to fill the specified dimensions and then crops any excess from the center. pad: Scales the image proportionally to fit within the specified dimensions and pads the remaining area with a fill color to match the target dimensions. fixed: Resizes the image to the specified width and height, ignoring the original aspect ratio. Each mode is illustrated in Scaling calculation methods. Note If you specify the `m` parameter with either the `w` or `h` parameter, the `l` and `s` parameters are ignored.
l	Specifies the longest side of the output image, in pixels. Note The longest side is the greater of the width and height. For example, for a 100 px × 200 px image, its longest side is 200 px and its shortest side is 100 px.	[1,16384]
s	Specifies the shortest side of the output image, in pixels.	[1,16384]
limit	Specifies whether to allow upscaling when the target dimensions are larger than the original image dimensions. Important By default, if the target dimensions are larger than the original, the original image is returned. To allow upscaling, set the parameter `limit` to 0.	1 (default value): Prevents upscaling. If the target dimensions exceed the original, the original image is returned. 0: Allows the image to be upscaled if the target dimensions are larger than the original. Note For animated images, you can only scale them down by specifying a width and height. Proportional scaling and upscaling are not supported.
color	Sets the padding color when the scaling mode is pad.	The RGB color value. For example, 000000 represents black and FFFFFF represents white. Default value: FFFFFF (white)

Note

If you specify only the width or only the height:
- When the scaling mode is lfit, mfit, or fixed, the image is scaled proportionally. For example, if the source image is 256 px × 144 px and you scale its height to 100 px, the width is scaled to 178 px.
- When the scaling mode is pad or fill, the width and height of the source image are scaled to the specified values. For example, if the source image is 256 px × 144 px and you scale the height to 100 px, the width is also scaled to 100 px.
If you specify only the l or s parameter, the image is scaled proportionally to the specified side length. The m parameter is ignored.
When both l and s are specified, the m parameter determines the scaling behavior. The aspect ratio is always preserved. If the m parameter is not specified, the default lfit mode is used.

Scaling methods

Original image size

Target size

Scaling mode

Scaled size

200 px × 100 px

150 px × 80 px

lfit (default)

Scales the image proportionally to create the largest thumbnail that fits within the target dimensions.

150 px × 75 px

lfit

mfit

Scales the image proportionally to create the smallest thumbnail that completely covers the target dimensions.

160 px × 80 px

mfit

fill

Scales the image proportionally to completely cover the target width and height, then crops the excess to match the target dimensions.

150 px × 80 px

fill

pad

Scales the image proportionally to fit within the target width and height, then pads the remaining area with a solid color to match the target dimensions.

150 px × 80 px

pad

fixed

Scales the image to the exact width and height, ignoring its aspect ratio. This may distort the image.

150 px × 80 px

fixed

Note

For the lfit and mfit modes, if a scaling calculation results in a decimal value, the dimensions are rounded to the nearest integer.

Examples

Scale down proportionally

Append ?x-oss-process=image/resize,p_{percentage} to an image URL to scale it proportionally. image/resize specifies the resize operation; p specifies the percentage. A p value in [1, 100] scales the image down. The value of p must be a positive integer.

Example

The following is an example of using ?x-oss-process=image/resize,p_50 to resize an image to 50% of its original size:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,p_50
Dimensions	2500 x 1875 px	1250 x 938 px

Scale up proportionally

Append ?x-oss-process=image/resize,p_{percentage} to an image URL to scale it proportionally. image/resize specifies the resize operation; p specifies the percentage. A p value in [100, 1000] scales the image up. The value of p must be a positive integer.

Example

The following is an example of using ?x-oss-process=image/resize,p_120 to scale up an image to 120% of its original size:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,p_120
Dimensions	2500 x 1875 px	3000 x 2250 px

Fixed-width scale down

Append ?x-oss-process=image/resize,w_{width} to an image URL to scale it proportionally to the specified width. image/resize specifies the resize operation; w specifies the desired width. The value range of w is [1,16384]. The value of w must be a positive integer.

Example

The following is an example of using ?x-oss-process=image/resize,w_200 to scale down an image to a fixed width of 200 pixels and a proportional height:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,w_200
Dimensions	2500 x 1875 px	200 x 150 px

Fixed-width scale up

Append ?x-oss-process=image/resize,w_{width} to an image URL to scale it proportionally to the specified width. image/resize specifies the resize operation; w specifies the desired width. The value of w must be in the range of [1,16384]. The value of w must be a positive integer.

Important

By default, if the target dimensions are larger than the source image, OSS returns the source image. To allow upscaling, you must add the limit_0 parameter.

Example

The following is an example of using ?x-oss-process=image/resize,w_3000,limit_0 to scale up an image to a fixed width of 3000 pixels while scaling the height proportionally:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,w_3000,limit_0
Dimensions	2500 x 1875 px	3000 x 2250 px

Fixed-height scale down

Append ?x-oss-process=image/resize,h_{height} to an image URL to scale it proportionally to the specified height. image/resize specifies the resize operation; h specifies the desired height. The value range for h is [1,16384]. The value of h must be a positive integer.

Example

The following example uses ?x-oss-process=image/resize,h_100 to scale down an image to a fixed height of 100 pixels and a proportional width:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,h_100
Dimensions	2500 x 1875 px	133 x 100 px

Fixed-height scale up

Append ?x-oss-process=image/resize,h_{height} to an image URL to scale it proportionally to the specified height. image/resize specifies the resize operation; h specifies the desired height. The value of h is in the range of [1,16384]. The value of h must be a positive integer.

Important

By default, if the target dimensions are larger than the source image, OSS returns the source image. To allow upscaling, you must add the limit_0 parameter.

Example

The following example uses ?x-oss-process=image/resize,h_2000,limit_0 to set the image height to 2000 pixels and scale the width proportionally.

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,h_2000,limit_0
Dimensions	2500 x 1875 px	2667 x 2000 px

Scale by longer edge

Scales the image based on the specified longer edge. The shorter edge adjusts proportionally. The m parameter has no effect in this mode.

Append image/resize,l_{length} to an image URL. image/resize specifies the resize operation; l specifies the longer edge. The value range for l is [1,16384], and the value of l must be a positive integer.

Important

By default, if the target dimensions are larger than the source image, OSS returns the source image. To allow upscaling, you must add the limit_0 parameter.

Example

The following is an example of using ?x-oss-process=image/resize,l_200 to scale an image by setting the longer edge to 200 and proportionally scaling the shorter edge:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,l_200
Dimensions	2500 x 1875 px	200 x 150 px

Scale by shorter edge

Scales the image based on the specified shorter edge. The longer edge adjusts proportionally. The m parameter has no effect in this mode.

Append image/resize,s_{length} to an image URL. image/resize specifies the resize operation; s specifies the shorter edge. The value of s must be in the range of [1,16384], and the value of s must be a positive integer.

Important

By default, if the target dimensions are larger than the source image, OSS returns the source image. To allow upscaling, you must add the limit_0 parameter.

Example

The following is an example of using ?x-oss-process=image/resize,s_200,limit_0 to set the shorter edge to 200 and scale the longer edge proportionally:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	Processed image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,s_200
Dimensions	2500 x 1875 px	267 x 200 px

Scale and pad

Resizes an image to fit within the specified width and height while preserving its aspect ratio, then pads the remaining space with a color.

Append image/resize,m_pad,w_{width},h_{height},color_{RGB} to an image URL. image/resize specifies the resize operation; m_pad scales the image to fit within the specified w and h. The color parameter sets the padding color (default: white). w is the desired width and h is the desired height. Both w and h accept values in [1,16384]. The values of w and h must be positive integers.

Examples

The following is an example of using ?x-oss-process=image/resize,m_pad,w_100,h_100 to resize an image by padding to a fixed width and height of 100 pixels:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,m_pad,w_100,h_100
Dimensions	2500 x 1875 px	100 x 100 px

The following is an example of using ?x-oss-process=image/resize,m_pad,w_100,h_100,color_FF0000 to scale an image by padding, fixing both the width and height at 100 pixels and setting the padding color to red:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,m_pad,w_100,h_100,color_FF0000
Dimensions	2500 x 1875 px	100 x 100 px

Scale and crop

Proportionally scales an image to cover the target dimensions, then crops excess from the center.

Append image/resize,m_fill,w_{width},h_{height} to an image URL. image/resize specifies the resize operation; m_fill scales the image to cover the rectangle defined by w and h, then crops the excess. w specifies the width and h specifies the height. Both w and h accept values in [1,16384]. The values of w and h must be positive integers.

Example

The following is an example of using ?x-oss-process=image/resize,m_fill,w_100,h_100 to center-crop and scale an image to a fixed width and height of 100 pixels:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,m_fill,w_100,h_100
Dimensions	2500 x 1875 px	100 x 100 px

Force-scale

Resizes an image to the exact specified width and height, ignoring the original aspect ratio. This may distort the image.

Append image/resize,m_fixed,w_{width},h_{height} to an image URL. image/resize specifies the resize operation; m_fixed applies forced scaling. w represents the desired width and h represents the desired height. Both w and h accept values in [1,16384]. The values of w and h must be positive integers.

Example

The following is an example of using ?x-oss-process=image/resize,m_fixed,w_100,h_100 to force-scale an image to a fixed width and height of 100 pixels:

Item	Source image	Processed image
Preview
URL	Source image URL: https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg	https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,m_fixed,w_100,h_100
Dimensions	2500 x 1875 px	100 x 100 px

Billing

Image scaling incurs the following fees. For pricing details, see OSS Pricing.

Image processing fees: Usage within the free tier is free of charge. If your usage exceeds the free tier, fees are based on the size of the processed source image. For billing details, see Data processing fees.

API	Billable item	Description
GetObject	GET requests	You are charged request fees based on the number of successful requests.
	Outbound traffic over the Internet	If you call the GetObject operation by using a public endpoint, such as oss-cn-hangzhou.aliyuncs.com, or an acceleration endpoint, such as oss-accelerate.aliyuncs.com, you are charged fees for outbound traffic over the Internet based on the data size.
	Retrieval of IA objects	If IA objects are retrieved, you are charged IA data retrieval fees based on the size of the retrieved IA data.
	Retrieval of Archive objects in a bucket for which real-time access is enabled	If you retrieve Archive objects in a bucket for which real-time access is enabled, you are charged Archive data retrieval fees based on the size of retrieved Archive objects.
	Transfer acceleration fees	If you enable transfer acceleration and use an acceleration endpoint to access your bucket, you are charged transfer acceleration fees based on the data size.

Related APIs

For advanced customization, make REST API requests directly. This requires manually calculating the signature. Signature Version 4 (Recommended).

To process an image, add image resizing parameters to the GetObject operation. For more information, see the GetObject operation.

GET /oss.jpg?x-oss-process=image/resize,p_50 HTTP/1.1
Host: oss-example.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: SignatureValue

FAQ

Ineffective scaling parameters

If you are using a CDN domain, this issue can occur if the Ignore Parameters feature is enabled. When active, CDN removes all query string parameters before forwarding the request to OSS, so OSS returns the unprocessed image. Disable the Ignore Parameters feature to resolve this. Ignore Parameters. Note that disabling this feature means URLs with different parameters are treated as unique requests, which increases back-to-origin requests and can lower your cache hit ratio.

Ineffective image upscaling

When you scale an image to dimensions larger than its original size, you must set the limit parameter to 0. Otherwise, the upscaling operation fails.

For example, the following URL scales an image with an original height of 1875 px to a new height of 2000 px:

https://oss-console-img-demo-cn-hangzhou-3az.oss-cn-hangzhou.aliyuncs.com/example1.jpg?x-oss-process=image/resize,h_2000,limit_0

Image persistence

By default, OSS processes images on-the-fly without saving results. For frequently accessed processed images (thumbnails, crops, format conversions), use the image processing persistence feature to save results to a specified bucket. Image processing persistence.

Accessing private scaled images

Use a signed URL to access processed private images. How to obtain the access URL after an object is uploaded.

Image scaling fees

Image scaling incurs image data processing fees, which are billed based on the actual size of the source image being processed. Image scaling includes a 10 TB per month free tier. Usage beyond this free tier is billed at a rate of 0.025 CNY per GB.

Egress traffic billing

Egress traffic charges are based on the size of the scaled image, not the source image. For example, if a 20 MB source image is scaled down to 2 MB, you are charged for 2 MB of egress traffic.

WebP decoding errors

This error occurs if the source image is an animated WebP file. To resolve this issue, submit a ticket to enable the animated WebP decoding feature.