Overview

Image compression refers to reducing an image’s size as much as possible without changing its quality, to reduce its cost for storage and traffic and speed up access.

CI launched the HEIF compression feature to convert images into HEIF format that offers an ultra-high compression ratio. HEIF offers over 80% smaller file sizes at the same quality compared with JPG. iOS has adopted HEIF as the default image format, and Android P has native support for this format.

Restrictions

• Format: Images in JPG, PNG, BMP, WebP, TPG, AVIF, or other formats can be converted into HEIF.
• Size: The input image cannot be larger than 32 MB, with its width and height not exceeding 30,000 pixels, and the total number of pixels not exceeding 250 million. The width and height of the output image cannot exceed 9,999 pixels. For an input animated image, the total number of pixels (Width x Height x Number of frames) cannot exceed 250 million pixels.
• Number of frames (for animated images): For GIF, the number of frames cannot exceed 300.

Prerequisites

To use HEIF compression, enable the image advanced compression feature for your bucket on the bucket’s configuration page. For more information, please see Setting Image Advanced Compression.

How to Use

CI uses the imageMogr2 API to provide the HEIF compression feature.

An image can be processed:

• Upon download
• Upon upload
• In cloud

Note：

HEIF compression is billed at image advanced compression rates.

API Format

1. Processing upon download

download_url?imageMogr2/format/heif

2. Processing upon upload

PUT /<ObjectKey> HTTP/1.1
Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
Date: GMT Date
Authorization: Auth String
Pic-Operations: 
{
"is_pic_info": 1,
"rules": [{
  "fileid": "exampleobject",
  "rule": "imageMogr2/format/heif"
}]
}

3. Processing in-cloud data

POST /<ObjectKey>?image_process HTTP/1.1
Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
Date: GMT Date
Content-length: Size
Authorization: Auth String
Pic-Operations: 
{
"is_pic_info": 1,
"rules": [{
  "fileid": "exampleobject",
  "rule": "imageMogr2/format/heif"
}]
}

Note：

Processing upon download is used as an example here, which does not store the output image in a bucket. If you need to store the output image, use Processing upon upload or Processing in-cloud data instead.

Parameters

Example

Assume that the input image is a 1,335.2 KB image in PNG format, as shown below:

You can convert the image into HEIF format using the following URL:

http://example-1258125638.cos.ap-shanghai.myqcloud.com/sample.png?imageMogr2/format/heif

Compression ratio comparison