Derivative images in unexpected format

Perceptual quality lightens the weight of your images while maintaining the best visual quality. This is done by intelligently calculating and applying the precise degree of compression that balances maximum byte reduction against visual quality. The resulting reduction in quality is imperceptible to the human eye.

Previewing the impact of perceptual quality on your images can help you better understand why some images were not converted to the expected format. For example, you may expect the images served to a Google Chrome browser to be in WebP or AVIF format. However, if conversion to this format would result in a perceptible reduction in visual quality, the image will be compressed and converted to another format that retains the perceptual quality of the original image.

See Create perceptual quality previews for guidance on creating these previews.