If you're like me, you've been asked "why is this page so slow?" more times than you'd like to admit — and the answer is almost always images. A single unoptimized hero image can add 3-5MB to your page load. So I spent a weekend testing free image compression tools to see which ones actually deliver.
Here's what I found.
The Contenders
I tested each tool with the same set of 10 images (mix of PNGs and JPEGs, ranging from 500KB to 8MB) and compared output quality, file size reduction, and overall experience.
1. TinyPNG
Website: tinypng.com
The OG of online image compression. TinyPNG has been around forever and it just works.
Pros:
- Excellent compression ratios (typically 60-80% reduction)
- Supports PNG, JPEG, and WebP
- Has a great API for automation
- Photoshop/Figma plugins available
Cons:
- Free tier limited to 20 images per batch, max 5MB each
- Images are uploaded to their servers (privacy consideration)
- No offline option
If you need an API for your build pipeline, TinyPNG is hard to beat. The free tier gives you 500 API calls/month.
2. Squoosh
Website: squoosh.app
Google's open-source image compression app. The side-by-side comparison slider is genuinely useful.
Pros:
- Runs in the browser — no uploads to external servers
- Real-time quality preview with slider comparison
- Supports modern formats (AVIF, WebP, JPEG XL)
- Open source (you can self-host it)
Cons:
- One image at a time (no batch processing)
- CLI tool exists but requires Node.js setup
- Development has slowed down significantly
For single images where you want fine-grained control over quality settings, Squoosh is excellent. The format conversion to AVIF alone can save you 50%+ over JPEG.
3. Compresso
Website: compresso.io
This one surprised me. Compresso runs entirely in your browser — your images never leave your machine.
Pros:
- 100% client-side processing (nothing uploaded anywhere)
- No file size limits, no daily caps
- Completely free, no account required
- Supports batch processing
- Great for sensitive/private images
Cons:
- Processing speed depends on your device
- Fewer output format options than Squoosh
- Newer tool, smaller community
If privacy matters to you (client projects, medical images, internal docs), Compresso is the clear winner. I've been using it for client work where I can't upload assets to third-party servers. The fact that it's genuinely unlimited with no catches is refreshing.
4. ShortPixel
Website: shortpixel.com
ShortPixel is more of a full-service image optimization platform, but their free tier is worth mentioning.
Pros:
- Three compression levels (lossy, glossy, lossless)
- WordPress plugin is best-in-class
- PDF compression too
- Excellent quality at aggressive compression levels
Cons:
- Free tier: only 50 images/month
- Requires account creation
- Server-side processing (images are uploaded)
- Paid plans can get pricey for high-volume use
Best for WordPress users who want a set-it-and-forget-it solution. The glossy compression mode is a nice middle ground between lossy and lossless.
5. Optimizilla
Website: optimizilla.com
Simple, no-frills image compressor. You upload, it compresses, you download.
Pros:
- Dead simple UI
- Per-image quality slider
- Side-by-side preview
- Up to 20 images at once
Cons:
- JPEG and PNG only (no WebP/AVIF)
- Max 20 images per batch
- Server-side processing
- No API or automation options
- Ads on the site
Optimizilla does one thing and does it okay. It's fine for quick one-off compressions, but the lack of modern format support makes it feel dated in 2026.
Quick Comparison
| Tool | Client-side? | Batch? | Free Limit | Modern Formats |
|---|---|---|---|---|
| TinyPNG | ❌ | ✅ | 20/batch, 5MB | WebP |
| Squoosh | ✅ | ❌ | Unlimited | AVIF, WebP, JXL |
| Compresso | ✅ | ✅ | Unlimited | WebP |
| ShortPixel | ❌ | ✅ | 50/month | WebP, AVIF |
| Optimizilla | ❌ | ✅ | 20/batch | ❌ |
My Recommendation
There's no single "best" tool — it depends on your workflow:
- For build pipelines: TinyPNG's API
- For fine-tuning single images: Squoosh
- For privacy-sensitive batch work: Compresso
- For WordPress: ShortPixel
- For quick one-offs: Any of them, really
Honestly, I keep Squoosh and Compresso bookmarked and use them interchangeably. Both run in the browser, both are free, and between them they cover pretty much every use case I hit.
What tools are you using for image compression? Drop a comment — I'm always looking for new stuff to try.
Top comments (0)