About AI Image Upscaler
AI Image Upscaler doubles the resolution of any photo using Real-ESRGAN — a super-resolution model trained to recover edge detail rather than just interpolate pixels. Use it to rescue low-res screenshots, old phone photos, product shots that need to fill a larger canvas, or thumbnails you've lost the source for. The model runs on-device via transformers.js/WebAssembly. First run downloads ~50 MB of weights; after that every upscale is offline and your images stay in the browser.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Pick an image
Drop a JPG, PNG or WebP. Smaller inputs (under ~1500 px on the long edge) give the cleanest results because the model has room to invent detail.
- 2
Run the upscaler
Real-ESRGAN runs on your CPU/GPU via WebAssembly. A 512×512 image upscales in a few seconds on a modern laptop; large inputs take longer.
- 3
Download the 2× output
Save the upscaled image. Compare side-by-side with the original to see the recovered edges and texture.
Related tools
Browse allRemove image backgrounds with an on-device AI model. Downloads once (~25MB), then works offline. Your photos never leave your browser.
Change dimensions with high-quality resampling.
Shrink JPEG, PNG, and WebP without visible quality loss.
Convert between PNG, JPG, and WebP in seconds.
Frequently asked questions
Are my files uploaded to a server?
No. Every tool on SnapToolz runs entirely inside your browser using JavaScript and WebAssembly. Your file is read locally, processed in memory, and the result is offered as a download. Nothing is sent to a server — there isn't one to send to.
Can it upscale by more than 2×?
The model is trained for a 2× factor. To go further, run the result back through the upscaler — a second pass gives you 4×. Quality holds well for 2× and is still good at 4× on photo-like inputs; very small inputs (under 200 px) will show some hallucinated detail.
Is the output AI-generated?
Yes. Real-ESRGAN invents plausible high-frequency detail that wasn't in the original pixels — so the upscaled image is a synthesis, not a true higher-resolution capture. For evidentiary, scientific or measurement use cases, the output is not a faithful representation. See /disclaimer.
Why does my upscale look soft or smudged?
Real-ESRGAN expects natural photographic inputs. Cartoons, line art, screenshots of text, and heavily-compressed images can confuse the model — text in particular may become illegible. For pixel art and UI screenshots, a plain integer-nearest upscale in our image resizer usually looks better.
Does it work offline?
Yes. SnapToolz is a Progressive Web App. After your first visit, the app is cached on your device and every tool keeps working without an internet connection.
Is SnapToolz free?
Yes — every tool is 100% free with no sign-up, no watermark, no hidden tier. The whole platform is open source and we have no plan to gate features.