100% client-side privacy
Your images never leave the browser. No server storage, no analytics reading file content.
Optimize images right in your browser — no upload, no signup
Compress, resize, watermark and convert images in bulk. 100% private, 100% free, open source.
Everything you need to optimize images
No spyware, no embedded watermark, no subscription.
Bulk processing
Compress up to 3 images concurrently with real-time progress. Auto-apply prefix, suffix, numbering.
WebP & HEIC
Convert JPEG/PNG to WebP for 25-35% smaller files. Reads HEIC straight from iPhone.
Flexible watermarks
Add text or PNG logo with custom position, opacity and size. Up to 5 watermarks per image.
Preserve EXIF
Optionally keep camera info, GPS coordinates and timestamps when compressing JPEG → JPEG.
3 compression presets
Light keeps quality high, medium balances both, max squeezes out the most savings.
Drag to reorder
Rearrange files before exporting zip. Watermarks are also drag-and-drop to layer as you like.
Save presets
Save multiple config sets for different workflows. Export as JSON, reuse on any device.
Just 3 steps
No learning curve, no docs to read.
- 1
Drop your images
Drag-drop, click to browse, or press Ctrl/⌘ + O. Supports JPG, PNG, HEIC, WebP.
- 2
Customize
Pick preset, format, size, naming, watermark. Apply to the whole batch.
- 3
Download
Download per file or grab everything as a zip. Duplicate names handled.
How it compares
Why pick Image Optimizer?
| Feature | Image Optimizer | TinyPNG | Squoosh |
|---|---|---|---|
| 100% client-side | Yes | No | Yes |
| Unlimited free | Yes | Limited | Yes |
| Bulk processing | Yes | Limited | No |
| Text + image watermark | Yes | No | No |
| Custom resize | Yes | No | Yes |
| Bulk naming + numbering | Yes | No | No |
| HEIC (iPhone) support | Yes | No | No |
| Saved presets | Yes | No | No |
Comparison based on each tool's free tier at publish time. Spot something wrong? Open an issue on GitHub.
Frequently asked questions
The most common things people want to know.
Does the app upload my images to a server?
No. All compression, resizing, and watermarking happens inside your browser via the Canvas API. You can disconnect from the network after loading the page and the app keeps working.
Do I need to create an account?
No. No accounts, no tracking cookies, no email capture. Your settings live in your browser's localStorage.
Is there a file count or size limit?
No limit on file count. Per-file size depends on your browser RAM — in practice, compressing 50MB images works fine on an 8GB machine.
WebP vs JPEG: which format should I pick?
WebP cuts 25-35% off JPEG file size at the same quality and is supported by all modern browsers. Stick with JPEG only if you need compatibility with old software or clients still on IE.
Does the app preserve EXIF metadata (GPS, capture time) when compressing?
Yes. Enable "Preserve EXIF metadata" in Settings. It only applies to JPEG → JPEG since WebP uses a different metadata format.
Can I compress many images and add watermarks at the same time?
Yes. Drop dozens of images, add up to 5 watermarks (text or PNG logo) per image. The app processes 3 images in parallel to avoid freezing the browser, then exports a single zip.
Does the app work offline?
Yes. The app is a Progressive Web App (PWA). After your first visit, the entire app is cached on your device, allowing it to load instantly and function 100% offline without any internet connection.
Is the source code public?
Yes, hosted on GitHub under the MIT license. Self-host, fork, modify, or send a pull request. Link in the footer.
Ready to optimize?
Free, no upload, no signup. Your presets save automatically for next time.
Open app →