There are plenty of free image compression tools and websites out there, but they vary widely in safety, supported formats, and ease of use. This article compares 5 carefully selected free tools for JPEG, PNG, and WebP compression, evaluated on safety, features, and supported platforms. Whether you need iPhone compatibility, offline support, or server-free processing, you will find the right tool here.
Three Things to Look for in a Compression Tool
1. Safety (Where Your Files Go)
Images often contain private photos or confidential materials, so whether files are uploaded to a server is the most important factor.
- Browser-based processing: Files never leave your device — safe and private (works offline too)
- Server-based processing: Files are uploaded to a server (check the deletion policy)
2. Format Support and Features
Check whether the tool supports major formats like JPEG, PNG, and WebP, and whether it offers quality adjustment and format conversion.
3. Usage Limits and Platform Support
Many free tools have file count or size limits. Also consider whether the tool works from iPhone and Android browsers, and whether it requires installation.
Comparison Table
| Tool | Processing | Formats | Registration | Limits | Offline | Mobile |
|---|---|---|---|---|---|---|
| sakutto | Browser | JPEG, PNG, WebP, HEIC | None | None | Yes | Yes |
| TinyPNG | Server | JPEG, PNG, WebP | None | 20/day | No | Yes |
| Squoosh | Browser | JPEG, PNG, WebP, AVIF | None | None | Yes | Yes |
| iLoveIMG | Server | JPEG, PNG, GIF | None (some features require it) | Free tier limited | No | App available |
| GIMP | Local | Nearly all formats | None | None | Yes | No |
Detailed Reviews
sakutto (sakutto.ai)
sakutto's image compressor stands out because all processing happens entirely in your browser. Your image files are never sent to any server, making it safe for private photos and confidential materials.
Pros
- Files never leave your browser (complete privacy)
- No registration, no usage limits
- Supports JPEG, PNG, WebP, and HEIC with format conversion
- Quality slider for precise compression control
- Works in Safari on iPhone and Chrome on Android
- Batch compression with ZIP download
Cons
- Processing speed depends on your device performance
- AVIF format not supported
Free Tool
Image Compressor
Compress JPEG, PNG, WebP, and HEIC images. Adjust quality, remove Exif data, and convert formats.
Try it now →TinyPNG
A well-known compression service. Despite the name, it supports JPEG and WebP in addition to PNG.
Pros
- High-quality PNG compression (preserves transparency)
- WordPress plugin and API available
- Simple drag and drop interface
Cons
- Free tier limited to 20 images/day, 5MB each
- Files are uploaded to servers
- No manual quality adjustment (automatic compression only)
Squoosh (by Google)
An open-source compression tool developed by Google. Processes everything in-browser for strong safety.
Pros
- Browser-based processing — files never uploaded
- Advanced compression engines (AVIF, MozJPEG, OxiPNG)
- Real-time before/after quality comparison
- Completely free, no limits
Cons
- No batch compression (one image at a time)
- English-only interface
- Combining resize and compression can be cumbersome
iLoveIMG
A sister site to iLovePDF, offering compression, resizing, format conversion, and more.
Pros
- Rich feature set beyond compression (resize, crop, convert)
- Google Drive and Dropbox import supported
- Dedicated iOS/Android apps
Cons
- Files are uploaded to servers
- Free tier has feature and usage limits
- No WebP input support
GIMP (Free Software)
An open-source image editor capable of advanced compression alongside full image editing.
Pros
- Fully offline, local processing (safe)
- Supports nearly every image format
- Extremely fine-grained quality and compression settings
- Full image editing capabilities
Cons
- Requires download and installation
- Complex interface with a steep learning curve
- PC only — not available on mobile
Best Tool by Use Case
| If you need... | Best choice | Why |
|---|---|---|
| Maximum privacy | sakutto | Files never leave your browser |
| No signup, no limits | sakutto | Free, unlimited, no registration |
| Best PNG compression quality | TinyPNG | Specializes in high-quality PNG optimization |
| Before/after quality comparison | Squoosh | Real-time preview feature |
| Mobile app compression | iLoveIMG | Dedicated iOS/Android apps |
| Image editing + compression | GIMP | All-in-one editor and compressor |
| iPhone browser compression | sakutto | No app needed — works in Safari |
FAQ
Can I compress images for free and safely?
Yes. However, safety varies by tool. Server-based tools upload your files, so check their data handling policies. Browser-based tools like sakutto and Squoosh process everything locally, offering the highest level of safety.
What is the best free image compression site?
For the best balance of safety and ease of use, sakutto is recommended. It processes in-browser for safety, requires no registration, has no usage limits, and supports JPEG, PNG, WebP, and HEIC compression and conversion.
Can I compress images from iPhone?
iLoveIMG has a dedicated iOS app. However, sakutto works directly in Safari without any app — just open the browser and select your photos.
How do I compress PNG images for free?
sakutto, TinyPNG, and Squoosh all support PNG compression. TinyPNG specializes in high-quality PNG optimization while preserving transparency. sakutto also offers WebP conversion for even smaller files.
Can image compression tools compress images inside PDFs?
Image compression tools work on image files directly (JPEG, PNG, WebP, etc.). To compress images within a PDF, use a PDF compression tool, or extract the images, compress them individually, and reassemble the PDF.
Can I compress images offline?
sakutto and Squoosh work offline once the page is loaded in your browser. For fully offline compression, install desktop software like GIMP.
Summary
Choose an image compression tool based on safety, format support, and usage limits. For safety and convenience, sakutto processes in-browser with no registration. For PNG quality, TinyPNG is the specialist. For detailed quality comparison, Squoosh offers real-time previews. For mobile apps, iLoveIMG covers iOS and Android. Try a few free options and find the one that fits your workflow.
Free Tool
Image Compressor
Compress JPEG, PNG, WebP, and HEIC images. Adjust quality, remove Exif data, and convert formats.
Try it now →