Image Upscaler
Upscale images 2× or 4× using browser-based super-resolution. Improve image detail and sharpness while keeping your photos private on your device.
Drop your image here
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How to use Image Upscaler
Frequently Asked Questions
What does image upscaling do?
Upscaling increases an image's resolution. Ordinary resizing (bilinear or bicubic interpolation) only spreads the existing pixels out, which makes edges soft and blurry. This tool instead uses a super-resolution neural network that was trained on real photos to predict sharper edges and finer texture at the higher resolution.
Which model does this tool use?
Real-ESRGAN General x4v3 — the compact general-purpose model (SRVGGNetCompact, about 1.2 million parameters) released by the Real-ESRGAN authors (Wang et al., 2021) under the BSD-3-Clause license. It is a trained 4× super-resolution network, run in your browser with ONNX Runtime Web on your GPU (WebGPU) when available, otherwise on your CPU (WebAssembly).
Is my image uploaded to your servers?
No. Processing happens entirely in your browser. The only thing downloaded is the model file itself (about 4.9 MB, fetched once from Hugging Face and then cached by your browser) and the ONNX Runtime engine from the jsDelivr CDN. Your image never leaves your device.
What is 2× upscaling?
2× doubles the width and height (4× the pixel count), e.g. 1000×800 becomes 2000×1600. The model works natively at 4×; for 2× the 4× result is downsampled by exactly half with area averaging — the same approach Real-ESRGAN's own tools use. So 2× takes about as long as 4× but gives a smaller file.
What is 4× upscaling?
4× quadruples the width and height (16× the pixel count), e.g. 500×400 becomes 2000×1600. It is the model's native scale and is best for small images, thumbnails, and low-resolution photos.
Does upscaling restore missing detail?
Partly. It sharpens edges, reduces JPEG blockiness and blur, and can produce plausible texture, but it cannot recover information that was never captured. Fine detail it adds is the model's best guess: faces and small text can look slightly painted or smoothed, and very noisy or heavily compressed images may come out over-smoothed. Always check the result before using it where accuracy matters.
What formats are supported?
JPG, JPEG, PNG, and WebP up to 20 MB. Results can be downloaded as PNG (lossless), JPG, or WebP. Transparent PNGs are supported: the colors are upscaled by the model and the transparency channel is resized with standard high-quality resampling, because the model only handles color.
Why does upscaling large images take longer?
The model processes the image in 128×128 pixel tiles (with a small overlap so seams don't show), and larger images need more tiles. Speed depends heavily on your device: with WebGPU a typical 1 megapixel photo takes seconds to tens of seconds; on CPU only it can take a minute or more. The output is limited to 36 megapixels so the browser doesn't run out of memory.