We tested the top free image compressors on compression ratio, quality, privacy, and ease of use. Here are the results.
1. FileCurve — Best for Privacy + No Limits
100% browser-based. No file size limit (up to 50MB free), no monthly limit, no signup. Supports JPG, PNG, WebP, AVIF, GIF. Also has 45+ other tools for PDF, video, and audio.
Best for: Users who value privacy, need to compress many images, or want an all-in-one toolkit.
2. TinyPNG — Best Pure Compression Ratio
Server-based compression with an excellent algorithm for PNG and JPEG. Free tier limited to 20 images/month and 5MB each. Uploads your files to their servers.
Best for: Developers who need the best PNG compression and use fewer than 20 images/month.
3. Squoosh — Best for Advanced Control
Google's open-source image compressor. Runs in the browser (like FileCurve). Gives you fine-grained control over every compression parameter. Interface is more technical.
Best for: Developers and designers who want maximum control over output.
4. Compressor.io — Best UI for Casual Users
Clean, simple interface. Good compression quality. Free tier limited to 10MB and 10 files per session. Uploads to servers.
Best for: Occasional use for small files.
5. iLoveIMG — Best for Batch + Multiple Tools
Good image tool suite beyond just compression. Includes resize, crop, watermark, and more. Free tier is limited; full features require subscription.
Verdict
For most users: FileCurve for privacy and no limits, TinyPNG if you need the best PNG compression and don't mind the 20/month limit.