AI Image Upscaler — Upscale Images 2× or 4× in Your Browser

AI super-resolution without uploading your photos

Classic resizing stretches existing pixels, so an enlarged photo looks soft and blocky. An AI image upscaler instead uses a neural network trained on millions of image pairs to predict how sharp edges and fine textures should look at the higher resolution. This tool runs the open Swin2SR super-resolution models directly in your browser with Transformers.js and ONNX Runtime. The 2× mode uses the classical Swin2SR model, which is faithful to clean images such as renders, screenshots and good photos. The 4× mode uses the real-world Swin2SR model trained with BSRGAN-style degradations, which copes better with noise and JPEG compression in everyday pictures. Your image is processed on your own device and is never sent to a server.

Model download, speed and memory

On first use the model weights are downloaded once from the Hugging Face hub and cached by the browser: about 22 MB for the compact 8-bit version used on the WebAssembly (CPU) backend, or about 54 MB for the full-precision version used on WebGPU. The ONNX runtime itself comes from the jsDelivr CDN. If your browser supports WebGPU, the graphics card does the work and a typical photo is ready in seconds; otherwise the CPU is used, which is slower but works everywhere. To keep memory use low, the image is split into small overlapping tiles that are upscaled one after another and stitched back together without visible seams; a progress bar shows each tile. Transparent PNGs keep their alpha channel, which is enlarged with Lanczos filtering.

Fast fallback and fair comparison

If the model cannot be downloaded or your device runs out of memory, the tool automatically switches to Lanczos resampling, a high-quality classic filter that needs no download and is far better than the browser's default stretching. You can also pick it yourself for a quick result. When the job finishes, drag the before/after slider to compare the original, stretched to the same size, with the upscaled result, and switch to actual pixels to inspect details. The download is a lossless PNG at the new resolution.