imgopt – PNG And JPEG Image Optimization
Imgopt is a bash script that makes use of different image optimization command line tools to drastically reduce the size of your JPEG and PNG images with minimal loss in quality.
imgopt makes use of the command line tools
pngout to optimize your PNG images.
For optimizing JPEG images, it uses
jpegtran to strip color profiles from JPEG images and another tool
jfifremove to remove JFIF metadata.
imgopt on the other hand can be used to optimize both JPEG and PNG images.
imgopt script from the authors website.