I ran the same 10 images through five different online compressors and measured everything: output file size, visual quality loss, compression speed, and what happened to my data. Two of the five uploaded my photos to servers in jurisdictions I couldn’t identify. One silently downscaled my images. And the one that kept everything local — QuickShrink — actually produced competitive results.
Here’s the full breakdown.
The Test Setup
I selected 10 JPEG photos covering real-world use cases developers actually deal with:
- Product shots (3 images) — white background e-commerce photos, 3000×3000px, 4-6MB each
- Screenshots (3 images) — IDE and terminal captures, 2560×1440px, 1-3MB each
- Photography (2 images) — landscape shots from a Pixel 8, 4000×3000px, 5-8MB each
- UI mockups (2 images) — Figma exports with gradients and text, 1920×1080px, 2-4MB each
Total input: 10 files, 38.7MB combined. Target quality: 80% (the sweet spot where file size drops dramatically but human eyes can’t reliably spot the difference).
The five compressors tested:
- TinyPNG — the default most developers reach for
- Squoosh — Google’s open-source option (squoosh.app)
- Compressor.io — popular alternative with multiple format support
- iLoveIMG — widely recommended in “best tools” roundups
- QuickShrink — our browser-only compressor at tools.orthogonal.info/quickshrink
File Size Results: Who Actually Compresses Best?
Here’s where it gets interesting. I compressed all 10 images at roughly equivalent quality settings (80% or “medium” depending on the tool’s UI), then compared output sizes:
Average compression ratio (smaller = better):
- TinyPNG: 72.4% reduction (38.7MB → 10.7MB)
- Squoosh (MozJPEG): 74.1% reduction (38.7MB → 10.0MB)
- Compressor.io: 68.9% reduction (38.7MB → 12.0MB)
- iLoveIMG: 61.3% reduction (38.7MB → 15.0MB)*
- QuickShrink: 70.2% reduction (38.7MB → 11.5MB)
*iLoveIMG’s “medium” setting is more conservative than the others. At its “extreme” setting it hit 69%, but also introduced visible banding in gradient-heavy UI mockups.
Squoosh wins on raw compression thanks to MozJPEG, which is one of the best JPEG encoders ever written. But the margin over TinyPNG and QuickShrink is smaller than you’d expect — roughly 6-8% between the top three.
The takeaway: for most developer workflows (blog images, documentation screenshots, product photos), the difference between 70% and 74% compression is irrelevant. You’re saving maybe 200KB per image. What matters more is everything else.
Speed: Canvas API vs Server-Side Processing
This is where architectures diverge. TinyPNG, Compressor.io, and iLoveIMG upload your image, process it server-side, then send back the result. Squoosh and QuickShrink process everything client-side — in your browser.
Average time per image (including upload/download where applicable):
- TinyPNG: 3.2 seconds (upload 1.8s + processing 0.9s + download 0.5s)
- Squoosh: 1.4 seconds (local WebAssembly processing)
- Compressor.io: 4.1 seconds (slower uploads, larger queue)
- iLoveIMG: 2.8 seconds (fast CDN)
- QuickShrink: 0.8 seconds (Canvas API, no network)
QuickShrink is fastest because the Canvas API’s toBlob() method is essentially calling the browser’s built-in JPEG encoder, which is compiled C++ running natively. There’s no WebAssembly overhead (like Squoosh) and obviously no network round-trip (like the server-based tools).
Here’s what the core compression looks like under the hood:
// The heart of browser-based compression const canvas = document.createElement('canvas'); const ctx = canvas.getContext('2d'); canvas.width = img.naturalWidth; canvas.height = img.naturalHeight; ctx.drawImage(img, 0, 0); // This single call does all the heavy lifting canvas.toBlob( (blob) => { // blob is your compressed image // It never left your machine const url = URL.createObjectURL(blob); downloadLink.href = url; }, 'image/jpeg', 0.80 // quality: 0.0 to 1.0 );That’s it. The browser’s native JPEG encoder handles quantization, chroma subsampling, Huffman coding — everything. No library, no dependency, no server. The Canvas API has been stable across all major browsers since 2015.
The Privacy Test: Where Do Your Photos Go?
This is the part that should bother you. I ran each tool through Chrome DevTools’ Network tab to see exactly what happens when you drop an image:
- TinyPNG: Uploads to
api.tinify.com(Netherlands). Image stored temporarily. Privacy policy says files are deleted after some hours. You’re trusting their word. - Squoosh: ✅ 100% client-side. Zero network requests during compression. Service worker caches the app for offline use.
- Compressor.io: Uploads to their servers. I watched a 6MB photo leave my browser. Their privacy page is one paragraph.
- iLoveIMG: Uploads to
api3.ilovepdf.com. Files “deleted after 2 hours.” Servers appear to be in Spain (EU GDPR applies, which is good). - QuickShrink: ✅ 100% client-side. Zero network requests. Works fully offline once loaded. I tested by enabling airplane mode — still works.
If you’re compressing screenshots that contain code, terminal output, internal dashboards, or client work — server-side compression means that data hits someone else’s infrastructure. For a personal photo, maybe you don’t care. For a screenshot of your production database? You should care a lot.
The Hidden Gotcha: Silent Downscaling
I noticed something odd with iLoveIMG. My 4000×3000px landscape photo came back at 2000×1500px. The file was smaller, sure — but not because of better compression. It was because they halved the dimensions without telling me.
I double-checked: there was no “resize” option enabled. Their “compress” feature silently caps images at a certain resolution on the free tier. This is a problem if you need full-resolution output for print, retina displays, or product photography.
None of the other four tools altered image dimensions.
When to Use What: My Honest Recommendation
Use Squoosh when you need maximum compression and don’t mind a slightly more complex UI. The MozJPEG encoder is genuinely better than browser-native JPEG, and it supports WebP, AVIF, and other modern formats. It’s the technically superior tool.
Use QuickShrink when you want the fastest possible workflow: drop image, download compressed version, done. No format decisions, no sliders, no settings panels. The Canvas API approach trades 3-4% compression efficiency for massive speed gains and zero complexity. I use it daily for blog images and documentation screenshots — exactly the use case where “good enough compression, instantly” beats “perfect compression, eventually.”
Use TinyPNG when you’re batch-processing hundreds of images through their API and don’t have privacy constraints. Their WordPress plugin and CLI tools are well-maintained. At $0.009/image after the free 500, it’s cheap automation.
Skip iLoveIMG unless you specifically need their PDF tools. The silent downscaling and middling compression don’t justify using a server-side tool when better client-side options exist.
Skip Compressor.io — Squoosh does everything it does, client-side, with better compression.
The Broader Point: Why Client-Side Tools Win
The web platform in 2026 is absurdly capable. The Canvas API, WebAssembly, the File API, Service Workers — you can build tools that rival desktop apps without a single server-side dependency. And when your tool runs entirely in the user’s browser:
- No hosting costs — static files on a CDN, done
- No privacy liability — you never touch user data
- No scaling problems — every user brings their own compute
- Offline capable — works on planes, in cafes with bad wifi, wherever
This is why I build browser-only tools. Not because client-side compression is always technically best — Squoosh’s MozJPEG proves server-grade encoders can run client-side too via WASM. But because the combination of speed, privacy, and simplicity makes it the right default for 90% of developer workflows.
Try QuickShrink with your own images and see the numbers yourself. And if metadata privacy matters too, run those same photos through PixelStrip — it strips EXIF, GPS, and camera data the same way: entirely in your browser, with nothing uploaded anywhere. For managing code snippets without yet another Electron app, check out TypeFast.
Tools for Your Developer Setup
If you’re optimizing your development workflow, the right hardware makes a difference. A high-resolution monitor helps when comparing compression artifacts side-by-side (I use a 4K display and it’s the first upgrade I’d recommend). For photography workflows, a fast SD card reader eliminates the bottleneck of transferring images from camera to computer. And if you’re processing images in bulk for a client project, a portable SSD keeps your originals safe while you experiment with compression settings — never compress your only copy.
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References
- Google — “Squoosh: An open-source image compression web app”
- TinyPNG — “TinyPNG: Compress PNG images while preserving transparency”
- Compressor.io — “Compressor.io: Optimize and compress your images online”
- Mozilla Developer Network (MDN) — “Image optimization: Best practices for web performance”
- GitHub — “Squoosh GitHub Repository”
Frequently Asked Questions
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I ran the same 10 images through five different online compressors and measured everything: output file size, visual quality loss, compression speed, and what happened to my data. Two of the five uplo
Related Privacy Tools
- QuickShrink: Browser Image Compressor — The local-first compressor that won our benchmark
- PixelStrip: Stop Photos Broadcasting Your Location — Strip EXIF metadata before sharing
- What Is EXIF Data? Remove It Before Sharing — Why photo metadata matters for privacy
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One silently downscaled my images. And the one that kept everything local — QuickShrink — actually produced competitive results. Here’s the full breakdown.
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