You can adjust the quality of an image by compressing the image, changing the absolute quality value, or changing the quality coefficient. Dynamic Route for CDN (DCDN) allows you to compress images stored on DCDN nodes without changing the image format.

Note
  • To use image editing, you must first submit a ticket to activate this feature.
  • Image editing is a paid service. It is currently free of charge until further notice.

Compress images

You can compress an image without resizing the image or changing the image format. Image compression compromises image quality but helps reduce data transfer costs.

Change image quality

Parameters

Set the action to quality.

The following table describes the parameters.
Parameter Description Valid value
Q Specifies an absolute quality value. Image quality can be represented by an absolute value. You cannot adjust the image quality to a higher value.
0<Q<100. The value must be a multiple of 5. Other values are not supported.
Note A greater quality value represents a higher quality and a higher clarity. We recommend that you set Q to 95.
q Specifies a quality coefficient. Image quality can be adjusted based on the original quality and a quality coefficient.
0<q<100. The value must be a multiple of 5. Other values are not supported.
Note A greater quality value represents a higher quality and a higher clarity. We recommend that you set Q to 95.
Examples
  • Specify an absolute quality value: If you set image_process=quality,Q_90 and the current quality is 80, the attempt to adjust the image quality from 80 to 90 fails. The image quality remains at 80.
  • Specify a quality coefficient: If you set image_process=quality,q_90 to adjust an image whose current quality is 80, the image quality is adjusted to 72.