The Radical Image Optimization Tool (RIOT for short) was developed to be a free image optimizer that will let you to visually adjust compression parameters while keeping minimum filesize. It uses with a side by side (dual view) or single view interface to compare the original with the optimized image in real time and instantly see the resulting file size.

It is lightweight, fast and simple to use, yet powerful for advanced users. You will be able to control compression, number of colors, metadata settings and much more, and select image format (JPG, GIF or PNG) for your output file.

Features:

• open many image types including rare/scientific types
• save and optimize JPEG, GIF and PNG with a simple, clean user interface
• works in dual view: (original – optimized image) or single view (optimized image).
• Automatic preview of resulting image
• in-place compare function (alternativelly display the original image over the optimized image to notice small pixel changes)
• compress files to desired filesize threshold
• fast processing (all is done in memory);
• see instant results including resulting filesize
• batch support (process multiple files at once)
• transparency handling options
• decide if you want to keep metadata (comments, IPTC, Adobe XMP, EXIF profiles, ICC profiles).
• Unsupported metadata is removed
• transfer metadata between image formats (destination format must support them)
• common tools: pan and zoom, rotate, flip
• basic image adjustments: brightness, contrast, gamma, invert
• visually reduce number of unique colors for PNG and GIF images in order to reduce filesize
• (two quantization methods are available: Xiaolin Wu and NeuQuant neural net)
• resize image by using well known resample filters (ex: Lanczos3, Catmull Rom, Bicubic, and others)
• out-of-the-box support for external PNG optimizers (optipng, pngout, etc)
• the compression and the results are comparable to those of commercial products, even higher.
• Adaptive logarithmic tone mapping algorithm (Drago) used for HDR images

Input image types:

• common bitmap images as well as Adobe Photoshop PSD files
• popular HDR formats and RAW camera images
• rare/scientific types (up to 128 bpp, integer and floating point)

What's New in version 0.4.6:

• added Help file (not yet complete)
• DLL version: added flags for all JPEG chroma settings
• DLL version: the default chroma for RIOT_SaveToFile is now "medium" instead of "low"
• Batch mode: fixed a bug when using a bat file as external PNG optimizer and @echo off is not on the first line. This problem does not occur in normal mode.
• DLL version: fixed some sliders going nuts when pressed during tooltip display
• fixed preview executed twice when asked to resample big images
• Batch settings "Keep original date/time" and "Report file size changes" are now remembered at startup
• if "Report file size changes" is checked and the selected external optimizer is not installed the reported size is -100 percent or ~ -99.9 percent. Fixed !
• fixed error running same batch twice with external optimizer and "Keep original date/time is checked
• file is now set as modified only if OptimizePNG is successfully executed
• fixed related issues reported in the RIOT forum, with the external PNG optimizer implementation
• fixed a memory leak in FileIsWritetable
• avoid some file locking problems