Butteraugli allows you to define a goal for visual quality, and then run PNG, JPG, WebP lossy, and WebP lossless compressions. You can then choose the image that is the best balance of file size and Butteraugli level. Figure 7 shows an example of how Butteraugli was used to find the minimal JPG quality level before the visual distortion was high enough for a user could perceive a problem; the result is a roughly 65% reduction in file size.