Download RIOT, to optimize your jpg, gif, png images
RIOT (Radical Image Optimization Tool) is a free program that will help you optimize your jpg, gif and png images even in batch processing, previewing the resulting images. RIOT offers also a plugin for IrfanView.
Features: open multiple formats by looking first at the magic number (it does not need file extension to recognize format) including support for uncommon types (up to 128 BPP, integer and floating point. EX: hdr images, 16 bit grayscale, etc). Adaptive logarithmic tone mapping algorithm (Drago) used for HDR images; save and optimize JPEG, GIF and PNG with a simple interface; works in dual view: (original – optimized image) or single view (optimized image). Automatic preview of resulting image; compress files to desired file-size threshold; fast processing (all is done in memory); see instant results including resulting file-size; decide if you want to keep metadata (comments, IPTC, Adobe XMP, EXIF profiles, ICC profiles). Unsupported metadata is removed; common tools: pan and zoom, rotate, flip; resize image by using well known resample filters (ex: Lanczos3, Catmull Rom, Bicubic, and others); in-place compare function (alternativelly display the original image over the optimized image to notice small pixel changes).
I don’t like the way some features are implemented; e.g., you can not just paste the address of a folder for batch processing, but you have to browse for it in order to select it. Beyond such objections the program works fine.