Increase Image Resolution
More pixels with real detail in them — a super-resolution model doubles or quadruples the resolution of a photo on your device. Free, nothing uploaded.
Upscale
Cleans JPEG artefacts and noise while keeping detail — the right default.
About the model
Real-ESRGAN "general x4v3" (SRVGGNetCompact, BSD-3-Clause), 4.9 MB, fp32. Runs in a Web Worker with ONNX Runtime on your CPU, in 256-pixel tiles; the 2× option runs the 4× model and box-filters the result down, which is sharper than a native 2× would be. The three styles are the official weights blended with the "denoise" weights at 0, 0.5 and 1. Each style is cached on your device after its first download.
What this tool does
It runs Real-ESRGAN — a compact super-resolution neural network released under the BSD-3 licence — on your device, in a Web Worker with ONNX Runtime, to enlarge the image 2× with reconstructed edges and texture and compression artefacts removed. The 4.9 MB model downloads from this site once and is cached; the photo never leaves your browser. There is no queue, no credits and no watermark because no server does any work.
Resolution vs. DPI — a quick untangling
"Resolution" usually means pixel dimensions (1200×800), but printers and forms often talk about DPI or PPI (300 dpi). DPI is just a label: a 1200×800 image prints at 4×2.7 inches at 300 dpi, or 16×10.7 inches at 75 dpi. If a printer or a portal says "300 dpi at A4", what they need is enough pixels — about 2480×3508 — and that is what this tool adds. Metadata DPI numbers are not changed or needed.
How the pixels are added
Real-ESRGAN, a super-resolution network running in a Web Worker on your CPU, predicts the missing detail from what it learned on millions of images, producing 2× or 4× the pixel count with real edges and texture rather than interpolation blur. For print, go 2× or 4× here, then use the resizer to hit the exact pixel size the printer asks for.
Limits and honesty
- Super-resolution invents detail. It cannot make unreadable text readable or recover a face that was never captured.
- Inputs are capped at 2.1 MP for 2× and 1.05 MP for 4×; larger images are reduced first and the page says so.
- It is CPU-bound: about 15–40 s for a 1 MP image at 2× on a laptop, longer on a phone, with a progress counter and a cancel button.
The full tool with every option lives at Upscale Image.
Frequently asked questions
Is my photo uploaded?
No. The page is static and has no upload endpoint; your browser does the work on your own device and the result is saved straight back to your disk. The site's Content-Security-Policy only allows it to talk to its own origin, so it cannot send your file anywhere even by accident. Load the page, disconnect from the internet, and it still works.
Does this set the DPI to 300?
It adds pixels, which is what 300 dpi actually requires. DPI itself is a metadata number that most printers and portals either ignore or compute from pixel size — if a specific tool insists on seeing "300" in the file, any image editor can set it in one click without changing a pixel.
What resolution can I get?
Up to 4× the original in one pass — a 1000×750 photo becomes 4000×3000 (12 MP). Inputs are capped at 2.1 MP for 2× and 1.05 MP for 4×; larger images are reduced first.
Which model is it?
Real-ESRGAN "general x4v3" (Tencent ARC, BSD-3-Clause) converted to ONNX by us from the official weights, running with ONNX Runtime compiled to WebAssembly. The three styles are the official base/denoise weight blends.
Is it free? Any limits or watermark?
Free, no account, no watermark, no daily quota. Because nothing runs on our servers there is nothing to meter. The only limits are your device's memory — anything up to roughly 50 megapixels is fine on a modern phone or laptop.
Does it work on my phone?
Yes on recent phones; the model download is 4.9 MB and processing takes 30–90 s for a 1 MP image. Keep the tab in the foreground.