Help Center/ Object Storage Service/ Image Processing (Leaving soon. Moving to User Guide.)/ Changing Image Quality
Updated on 2024-08-09 GMT+08:00
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Changing Image Quality

You can edit code on OBS Console or make an API call to change the quality of an image.

To save space, you can compress JPG images. Table 1 describes the parameters.

This operation is represented by quality.

Table 1 Image compression parameters

Parameter

Value Description

Code Example

q

Relative quality of the image. The image is compressed to q% of the original. The value ranges from 1 to 100.

Formula for compression: Target quality = Original quality x q%

For example, if the original image quality is 100% and the relative quality is 80%, then the target image quality is 80%. If the original quality is 80% and the relative quality is 80%, then the target quality is 64%.

image/resize,w_100,h_100/quality,q_80

Q

Absolute quality of the image. The image is compressed into Q%. Q is irrelevant to and does not depend on the original image. The value ranges from 1 to 100.

Formulas for compression:

  • Original quality > Q%: target quality = Q%
  • Original quality = Q%: target quality = original quality = Q%
  • Original quality < Q%: target quality = original quality

For example, if the original image quality is 100% and the absolute quality is 80%, then the target image quality is 80%. If the original quality is 70% and the absolute quality is 80%, then the target quality is 70%.
  • q is valid only for JPG images.
  • If both q and Q are used, the output is based on Q.
  • q and Q are only valid for JPG images. For images in other formats, q and Q bring no effect and cause no impact.

Examples