This post provides a quick guide to change the quality of an image that is served from ImageKit. You can read a more detailed documentation here.
URL Transformation – Yes
Parameter – q (from 1 to 100)
Dashboard Setting – Yes
Settings > Image quality setting > Default Quality dropdown
1. Automatic quality selection without specifying quality in the URL
Recommended. The default quality value from your dashboard settings is selected in this case.
2. Quality 75
Generally considered a mid-range quality level (75-85) that is suitable for a lot of images.
3. Quality 40
Generally considered a low-range quality level as artefacts begin to appear in most of the images.
4. Quality 95
Generally considered a high-range quality level and is not necessary for most of the images because of now perceptible quality increase when compared to mid-range quality levels.
You can refer to the detailed documentation here to get more options about image quality (q).