RIOT 2024.1.0 – Free Image Optimizer

RIOT (Radical Image Optimization Tool) is a free image optimizer that will let you visually adjust compression parameters while keeping a minimum file size. It uses 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, simple, and powerful for advanced users. You can control compression, number of colors, metadata settings, and much more, and select image format (JPG, GIF, or PNG) for your output file.

Also, you can integrate RIOT as a plug-in in well-known software like GIMP, IrfanView, and XnView.

Main features of RIOT:

• open many image types including rare/scientific types
• save and optimize JPEG, GIF, PNG, and Web with a simple, clean user interface
• automatic optimization selects the most suitable format and parameters
• works in dual view: (original – optimized image) or single view (optimized image).
• automatic preview of the resulting image
• in-place compare function (alternatively display the original image over the optimized image to notice small pixel changes)
• compress files to the desired filesize threshold
• fast processing
• 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).
• 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 the number of unique colors for PNG and GIF images to reduce filesize
• (two quantization methods are available: Xiaolin Wu and NeuQuant neural net)
• resize images 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)