2× / 4× Image Upscaler
Double or quadruple a photo's resolution locally with Real-ESRGAN.
The first run downloads a ~67 MB model once. Later runs reuse it from the browser cache.
Beta: on desktop, 2× accepts up to 1400 px on the long edge and 4× accepts up to 700 px. Desktop output is capped at 2800 px; mobile devices use lower limits to avoid memory errors. Transparent areas are flattened to white. WebGPU is used when available; otherwise it falls back to CPU and can be slow.
This beta tool runs Real-ESRGAN in the browser. Add one or several photos, choose 2× or 4×, start the batch, and preview each result before downloading. 2× accepts inputs up to 1400 px on the long edge; 4× runs the model twice and accepts up to 700 px. The first run downloads about 67 MB; later runs reuse the cached model. Transparent areas are flattened to white.
What this page does
- 2× and 4× modes
- Batch upscale with previews
- Runs locally in the browser
- WebGPU with CPU fallback
- No upload and no login
FAQ
Is the output really 2× or 4×?
Yes. 2× doubles the width and height of the processed image. 4× runs the 2× model twice, producing four times the width and height.
Why is 4× limited to 700 px?
A 4× result has 16 times as many pixels as the input. The cap keeps the output at or below 2800 px and avoids browser memory errors.
Can I upscale more than one photo?
Yes. Add a batch, start it once, then preview each row. Use the close button on a row to remove it before downloading.
Why is there a size limit?
The model is heavy. Keeping the input at 1400 px or less avoids browser memory errors and very long runtimes.
What happens without WebGPU?
It falls back to CPU with WebAssembly. That still works, but it can take much longer.
Are my photos uploaded?
No. Downloading the model is the only network request; the image itself is processed in this browser.