RIOT 2026.9 — a new generation of the image optimizer
RIOT 2026.9 is the first release of the rebuilt Radical Image Optimization Tool — a free desktop image optimizer for macOS, Windows, and Linux. It keeps the idea that made RIOT useful in 2008: squeeze image files without a trip through a browser or a cloud, and see the result before you commit.
This is a new application, written for today’s machines. It is not a skin on the classic Windows build. What it offers:
New Optimization Engine
A high-performance parallel processing engine sits under 2026.9, and it will be the core of every RIOT optimizer version from here on. There are plans for a web version, a highly performant Linux image optimization server, and likely a cloud-hosted, API-accessible service.
The engine for those future server and cloud versions is built for high throughput, with horizontal scaling when demand requires it. If you are interested in any of these, contact us.
Automatic image optimization
Drop photographs, screenshots, or graphics in and choose an Auto preset — HQ, Standard, Eco, or Lossless. RIOT analyses each file: how many colours it really uses, whether it behaves like a photo or a drawing, how much texture it has, and how hard the original was already compressed. Those signals pick lossless versus lossy encoding, quality, chroma subsampling, and palette size. Manual mode is still there when you want every knob.
Multi-core batches
Optimization is parallel. The app runs one worker per CPU core so a folder of images is processed together, with a live progress bar, cancel, and a summary of files processed, elapsed time, and bytes saved.
Compare and preview
Double-click a file for a curtain compare of original and optimized. Pan, zoom, and drag the split. The preview is encoded with your current settings, not a guess — including animated frames. A hold-to-swap control lets you flip sides instantly. Image info lists attributes for both files side by side.
Only the visible crop is painted each frame, so a 12,000×8,000 photograph pans and zooms as cheaply as a snapshot. Smaller copies for zoomed-out views are built only when needed — fitting the window never pays for work you will not see. Zoomed out, the picture stays smooth; zoomed in past actual size, RIOT shows real pixels. That is faster to draw, and it is how you actually judge compression artifacts.
Formats and codecs
Open JPEG, PNG, WebP, GIF, TIFF, HEIC, and AVIF. Save to JPEG, PNG, WebP, and GIF. JPEG uses a high-efficiency encoder with progressive scans and careful chroma. PNG offers a slower maximum-compression pass. WebP can be lossless, near-lossless, or lossy. Optimal format tries a smaller container and keeps the source file when it is already smaller. Original format stays in a supported source type.
Resize, palettes, metadata, files
Resize by pixels or percent, with aspect lock and a choice of resample filter. Quantization (2–256 colours, dither, effort) is available for PNG, WebP, and GIF in manual mode. Metadata can be stripped or kept (EXIF, XMP, IPTC, ICC, and other). Transparency can be preserved, blended to a colour, or made opaque. File handling covers overwrite, backup, delete originals, and original timestamps.
Animation
GIF, WebP, and AVIF animations keep their frames unless you ask to flatten to the first frame. Compare plays both sides with each file’s delays.
Desktop, your way
Light, dark, or system theme. English, Spanish, and Romanian, switchable at runtime. Bug reports and feature ideas go to the User Portal.
RIOT remains free. Work on the tool started in 2004; the first public release was in 2008. Version 2026.9 is the start of the cross-platform line — current, previous, and selected stable builds will stay listed on the download page, each with its changelog.