Comparison
Apolo vs ImageOptim.
ImageOptim is a Mac classic for making images lighter without changing them. Apolo also converts them to the new formats.
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In short
ImageOptim is a free, open-source Mac app: you drag images onto it and it makes them lighter without changing their format, lossless by default. It also handles animated GIFs and SVG.
Apolo, besides optimizing JPEG and PNG, converts to WebP, AVIF and JPEG XL, which weigh considerably less, and also runs on Windows and Linux.
Side by side
| What | Apolo | ImageOptim |
|---|---|---|
| Price | Free | Free |
| License | GPL-3.0 (open source) | GPL-2.0 or later (open source) |
| Where it runs | macOS, Windows and Linux, on x64 and ARM | macOS only (11 or later) |
| Your images | Never leave your computer | Never leave your computer |
| Formats it writes | WebP, AVIF, JPEG XL, JPEG (MozJPEG), PNG (OxiPNG) and QOI | Optimizes JPEG, PNG, GIF and SVG without changing format; doesn't write WebP or AVIF |
| Whole folders | Yes, in parallel and with subfolders | Yes, by dragging several |
| Command line | Yes, with the options of cwebp, cjpeg, oxipng, avifenc and cjxl | Yes |
| AI agents (MCP) | Yes, eleven tools | No |
| Measures the loss | Yes: SSIMULACRA 2, PSNR and SSIM, and quality by score | No; lossless by default |
What each one does better
What ImageOptim does better
- It optimizes SVG and animated GIFs, which Apolo doesn't write.
- It plugs into the Finder: drag and done, nothing to decide.
What Apolo does better
- It converts to WebP, AVIF and JPEG XL: at the same perceived quality, much lighter than an optimized JPEG or PNG.
- It shows the result and measures the loss with SSIMULACRA 2, with quality by score.
- It runs on macOS, Windows and Linux, and ships a server for AI agents.
Which to choose
ImageOptim
Making JPEG, PNG, GIF or SVG lighter without changing anything, on a Mac.
Apolo
Moving to modern formats, on any system, or seeing and measuring the loss.
Keep reading
- Apolo vs SquooshThe same engines; Squoosh in the browser and one by one, Apolo on the desktop, by folders and measuring the loss.
- Apolo vs TinyPNGTinyPNG on its servers and with limits; Apolo on your computer, free and unlimited.
- Apolo vs CaesiumTwo free desktop compressors: Caesium with JPG, PNG, WebP and TIFF; Apolo with AVIF, JPEG XL and loss measurement.