Instead of relying on the non-standardized quality metric for JPEG compression, let's make use of a dissimilarity check to hone in on an optimal quality setting for each JPEG to be compressed
Automatically find the ideal JPEG quality setting for a JPEG image by calculating the output images dissimilarity from the input JPEG. This frees us from having to rely on the unstandardized quality integer.
Place this script anywhere in your $PATH. Requires Bash >= 4.x
cjpeg-dssim jpegoptim /path/to/input-image.jpg
Supported encoders: * jpegoptim * mozjpeg