Radical Image Optimization Tool
A professional image optimizer for people who care about file size and picture quality. Automatic image optimization, multi-core batches, and a live original-versus-optimized preview — on macOS, Windows, and Linux. First released in 2008, and still free.
Desktop app for macOS, Windows, and Linux · Version 2026.9.1
Work on RIOT started in 2003 as a personal app. The first public release arrived in 2008 — a free optimization plugin for IrfanVIew and later GIMP, XnView and Paint.NET + standalone app, initially in a time when most “optimization” meant an export dialog in a few commercial programs. It may well have been the first dedicated standalone image optimizer. Twenty years on, 2026.9.1 rebuilds that idea for every desktop OS.
History & authorFrom cutting-edge automatic analysis and multi-core throughput down to themes and languages — the capabilities that matter when you compress a lot of pictures.
RIOT runs one optimization worker per CPU core, so a folder of photographs finishes in parallel instead of one file at a time. Progress is live, cancellable, and summarized when the batch completes — images processed, time elapsed, and bytes saved.
Open any file into a curtain compare of original vs optimized. Pan, zoom, and drag the divider. The preview follows your current format and quality settings — including animated frames — so you judge the result before writing a batch to disk.
Automatic image optimization classifies photos versus drawings, measures texture, and estimates how much quality is already in the file. RIOT then chooses lossless, near-lossless, or lossy encoding — and the right quality and chroma — from HQ down to Eco presets. You can still take full manual control.
JPEG encoding uses progressive scans, intelligent chroma, and high-efficiency compression that keeps photographs sharp at smaller sizes. PNG has a maximum-compression pass for graphics. WebP supports lossless, near-lossless, and lossy. Optimal format tries a smaller container and keeps the original when it already wins.
Open JPEG, PNG, WebP, GIF, TIFF, HEIC, and AVIF. Save to JPEG, PNG, WebP, and GIF — or keep the original container. Strip or preserve EXIF, XMP, IPTC, ICC profiles, and other metadata. Transparency can be kept, flattened to a colour, or made opaque.
Add files or whole folders, resize with aspect lock, and quantize palettes when you need fewer colours. File handling covers overwrite, backup, delete originals, and keeping timestamps. A confirmation step protects you before destructive options run.
Animated GIF, WebP, and AVIF keep their frames through optimization and through compare playback. Prefer a still? Flatten to the first frame. Duplicate GIF frames can be kept or dropped. The preview plays each side with its own delays.
Light, dark, or follow the system appearance. The interface is localized in English, Spanish, and Romanian, and you can switch language while the app is running. One binary, your preferred UI.
The desktop app is available for macOS, Windows, and Linux. We keep the current release, the previous one, and selected stable builds — each with its own changelog.
Apple Silicon. Drag the app into Applications.
64-bit installer. Replaces classic RIOT if it is present.
AppImage runs anywhere; .deb for Debian, Ubuntu, and Mint.
— The first release of the rebuilt Radical Image Optimization Tool: a native desktop image optimizer for macOS, Windows, and Linux, with automatic analysis, multi-core batches, and live compare.
Read the announcementReport a bug or suggest a feature. Votes from other users help decide what comes next.
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An image optimizer shrinks JPEG, PNG, WebP, and GIF files while keeping the picture looking right. That is image optimization: fewer bytes on disk and on the wire, same photograph. RIOT does this locally, in a desktop app.
Yes. RIOT has been a free standalone image optimizer since 2008. There is no account and no upload to a service.
The current desktop app ships for macOS, Windows, and Linux (AppImage and .deb).
