I have lots of images in png format (over 250k+ png). Properly formatting and compressing png images can save many bytes of data. How do I compress and optimize png images on my amazon cloud account so that I can save bandwidth on cloudfront cdn account? How do I use an image compressor to create lossless compression on PNG files, with no effect on image quality in bulk using Red Hat Enterprise Linux bash shell?

The following image format is recommended and used by big web sites such as Google / Yahoo / Amazon / Facebook etc:

1 PNG file format is recommended for web.
2 GIF file format is recommended for small size images.
3 JPG file format is recommended for high resolution photographic-style images.
4 Do not use BMPs or TIFFs.