AI Image Upscaler

Upscale images 2x or 4x with AI — free

🔒 Files never leave your browser

🔒 Your image is processed entirely in your browser. Nothing is uploaded to any server.

How to Use AI Image Upscaler

Upload your image

Drag and drop any JPG, PNG, or WebP image. For best speed, use images under 1024x1024. Your image stays in your browser and is never uploaded.

Choose upscale mode

Pick from 3 modes: 2x Fast (3.9MB Swin2SR), 2x Quality (8.6MB APISR GAN for sharper results), or 4x Enlarge (5.0MB APISR). Models download once and are cached.

Download the result

Click Upscale Image and wait 10-30 seconds. Compare original vs upscaled side by side, then download the high-resolution PNG.

Why Choose AllTools AI Image Upscaler?

  • Three AI models: 2x Fast, 2x Quality (GAN), 4x Enlarge
  • Swin2SR and APISR — state-of-the-art super-resolution neural networks
  • Runs 100% in browser — image never uploaded to any server
  • Models cached after first download (3.9-8.6MB) — works offline
  • Side-by-side comparison with dimension display
  • Download as full-resolution PNG without watermark
  • No account, no limits, completely free
  • Works on desktop and mobile browsers

Why Use This Tool

  • Complete privacy — your image never leaves your browser, verifiable in DevTools Network tab
  • Free forever — no $199 license like Topaz Gigapixel, no per-image fees
  • Three quality modes — choose speed vs quality based on your needs
  • Tiny models (3.9-8.6MB) — fast download, cached for offline use
  • No account, no watermark, no limits — just upload and upscale

How AI Image Upscaling Works

Traditional image resizing (bilinear, bicubic interpolation) simply stretches pixels, producing blurry results. AI upscaling uses neural networks trained on millions of image pairs (low-res and high-res) to learn what detail should exist at higher resolutions. This tool offers two model families: Swin2SR uses a Shifted Window Transformer architecture that processes the image in overlapping patches, generating sharp details while maintaining consistency across patch boundaries. APISR uses a GAN (Generative Adversarial Network) trained specifically for anime and photographic super-resolution, producing perceptually sharper results. All models run via ONNX Runtime in your browser using WebAssembly — no server processing, no upload, complete privacy.

When to Use Each Upscale Mode

Use 2x Fast (Swin2SR, 3.9MB) for quick previews, social media images, and batch workflows where speed matters more than maximum quality. Use 2x Quality (APISR GAN, 8.6MB) for photos you plan to print, portfolio images, or any case where perceptual sharpness is important — the GAN model adds realistic texture detail that the fast model smooths over. Use 4x Enlarge (APISR, 5.0MB) when you need to dramatically increase resolution — turning a 256x256 thumbnail into a usable 1024x1024 image. Note that 4x upscaling works best on images with clear subjects and good original quality. Very noisy or heavily compressed source images may show artifacts at 4x.

Related Resources

Frequently Asked Questions

Is my image uploaded to a server?
No. The AI models run entirely in your browser using ONNX Runtime via Transformers.js. Your image never leaves your device.
How long does upscaling take?
Typically 10-30 seconds depending on image size and your device. Smaller images (under 512x512) process in under 10 seconds. The first use downloads the model (3.9-8.6MB), then subsequent uses are faster.
What is the difference between the 3 modes?
2x Fast uses Swin2SR Lightweight (3.9MB) for quick 2x upscaling. 2x Quality uses APISR GAN (8.6MB) for sharper, more detailed 2x results. 4x Enlarge uses APISR (5.0MB) for quadrupling image dimensions.
What image formats are supported?
JPG, PNG, and WebP input. Output is always PNG to preserve maximum quality.
Is there a file size or resolution limit?
No strict limit, but images over 1024x1024 may take 30-60 seconds or more. For best experience, use images under 1024x1024.
Does it work offline?
After the first model download, yes. Models are cached in your browser. You can upscale images without internet.
How does this compare to Topaz Gigapixel?
Topaz Gigapixel costs $199 and requires desktop software. This tool is free, runs in your browser, and uses similar neural network technology. For professional batch processing, Topaz may offer more control.
Can I upscale the same image multiple times?
Yes, but AI upscaling adds detail based on learned patterns. Upscaling an already-upscaled image gives diminishing returns. For best quality, start from the original low-resolution source.

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