Online Tool Store
Image Upscaler
Enlarge a JPG, PNG, or WebP image 2x, 3x, or 4x using an on-device AI super-resolution model. Runs entirely in your browser — nothing is uploaded to a server.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
How it works
- Choose an image and pick a scale — 2x, 3x, or 4x.
- Click Upscale image — an AI super-resolution model runs directly in your browser to enlarge it.
- Compare the original and upscaled previews, then download the result as a PNG.
How the AI upscaling works
A simple resize (bicubic or bilinear interpolation) can only blend the pixels an image already has, so edges and fine texture get soft as you enlarge it. This tool instead runs a convolutional neural network — an ESRGAN-style model with an RDN (Residual Dense Network) architecture — trained on many pairs of low-resolution and high-resolution images, so it learns to predict the sharp detail a plain resize would just blur:
output pixels = model(input pixels) → width × scale, height × scale
The model has a fixed input size, so for images larger than that it automatically splits the picture into overlapping tiles, upscales each tile, and stitches the results back into one image — which is also why a bigger source image or a higher scale takes noticeably longer: there are more tiles for the network to process.
FAQ
Does my image get uploaded anywhere?
No. The AI model and TensorFlow.js both run inside your browser tab — your image is decoded, upscaled, and encoded back to a PNG entirely on your device, and never touches a server.
What AI model does this use?
An ESRGAN-style super-resolution model (an RDN — Residual Dense Network — architecture) trained to predict realistic detail, running through TensorFlow.js's WebGL backend so your GPU does the work instead of a remote server.
Why does the first upscale take longer than the next one?
The first click downloads the model for your chosen scale (roughly 1MB) plus TensorFlow.js itself, since neither is loaded until you actually use the tool. Your browser caches both, so switching between images at the same scale is fast afterward.
Which image formats are supported?
Upload a JPG, PNG, or WebP file. The upscaled result always downloads as a PNG, so no detail is lost to re-compression on the way out.
Is there an image size limit?
No hard limit is enforced, but the output has 4, 9, or 16 times as many pixels as the original at 2x, 3x, and 4x, and it all runs on your device's own CPU/GPU. Very large source images or 4x on an older device can take a while — a few hundred pixels per side upscales in seconds.
Will this fix a badly blurred or low-quality photo?
It adds plausible, learned detail and sharper edges to a clear image at a higher resolution — it can't invent detail that was never captured, so it won't rescue a heavily blurred or very low-quality source the way it enhances a clean one.
How we compare
| Feature | Online Tool Store | Let's Enhance | Upscale.media |
|---|---|---|---|
| No file upload — runs in your browser | ✓ | ✗ | ✗ |
| No account required | ✓ | ✗ | ✓ |
| Unlimited free upscales | ✓ | Free trial credits only | Free tier is resolution-limited |
| Choose 2x, 3x, or 4x | ✓ | ✓ | ✓ |
Let's Enhance and Upscale.media both produce good results, but each sends your photo to their server to process it and gates full use behind an account or a limited free tier. If you'd rather keep the image on your own device and upscale as many as you like, Image Upscaler gets you there without uploading anything.