You can adjust the quality of an image by compressing the image, changing the absolute quality value, and changing the quality coefficient. Alibaba Cloud Content Delivery Network (CDN) allows you to compress images stored on CDN nodes without changing the image format.

Note
  • This feature is in private preview. To participate in the private preview, submit a ticket.
  • This feature is free of charge during the private preview. After it is officially released, it charges fees. For more information, see the product updates.

Compress images

This feature reduces the size of all images under a domain name without changing the resolution, format, or quality of the images.

Change the absolute quality value

Set the action to quality. The absolute quality value is specified by the Q parameter.
Note
  • The absolute quality value must be within 0 and 100, and be a multiple of 5. Other values are not supported.
  • A greater quality value represents a higher quality and a higher clarity.

Image quality can be represented by an absolute value. You cannot adjust the image quality to a higher value. For example, if you set image_process=quality,Q_90, the attempt to adjust the image quality from 80 to 90 fails and the image quality remains at 80.

Change the quality coefficient

Set the action to quality. The quality coefficient is specified by the q parameter.
Note
  • The absolute quality value must be within 0 and 100, and be a multiple of 5. Other values are not supported.
  • A greater quality value represents a higher quality and a higher clarity.

Image quality can be adjusted based on the original quality and a quality coefficient. For example, if you set image_process=quality,q_90 to adjust an image whose quality is 80, the image quality is adjusted to 72.