Its a good concept.File size is always an issue for webmasters especially when multiple images are used in any website.The smaller the size of images , better it is for search engines.
actually we were working to optimize the google page speed of ObviousIdea and Google suggests a lot to save space on png image with lossless compression, is anyone know if it is only the color palette to be reduced or there is something else ? ( not sure if we could add it to Light Image Resizer )
It's been a while since the original request, but color depth can now finally be set in Light Image Resizer version 5!
Just select Bitmap or PNG as the format and you will be able to select a supported bit depth. For JPEG and TIFF the color space (RGB, CMYK, etc) can be selected.