About AI Image Upscaler
This upscaler doubles or quadruples the width and height of your image. In AI mode it uses ESRGAN, a model trained to rebuild detail when enlarging, so edges and text come out sharper than with ordinary resizing. The model is small, about 1 to 3 MB, downloads once and runs inside your browser, so your image is never uploaded to a server.
Alongside AI there is a Classic method based on the Lanczos-3 algorithm. It is faster and handles larger images, but it is not AI, and every result says so clearly. If the model can't run on your device, or the image is larger than the AI limit, the tool switches to Classic and tells you why.
Why use it
- 2× or 4× upscaling with an ESRGAN model running on your device, with no upload.
- Two AI options: a light, fast model and a higher-quality, slower one.
- A Classic (Lanczos-3) fallback that always works, even if the AI libraries can't load.
- Every result is labelled: Made with AI (ESRGAN) or Classic upscale, not AI.
- A before/after slider and a PNG download with no extra compression.
- Clear size limits that keep phones from freezing, with the reason explained.
How to use
Upload an image
Drag an image onto the box or tap it to browse. JPG, PNG and WebP are supported.
Choose the scale
2× doubles the width and height; 4× makes each side four times larger, which is 16 times the pixels.
Choose a method
AI (ESRGAN) for the light model, AI higher quality for the larger model, or Classic for the fastest result without AI.
Upscale
Press Upscale and watch the percentage. The first time the model downloads, then the image is processed in small tiles.
Compare and download
Drag the slider to compare the original with the result, then press Download PNG. The file keeps your image name plus 2x or 4x.
Examples
A small, low-resolution logo
A 300×300 px logo you want on a business card: AI 4× gives you 1200×1200 with smoother edges than classic resizing.
An old phone photo
A 640×480 family picture upscaled 2× to 1280×960 looks better on a large screen or when shared.
A product image for a shop
The supplier sent 500×500 px images and your shop needs at least 1000 px. A 2× upscale solves it without a reshoot.
A large image on a phone
A 1200×900 photo is over the AI limit on a phone, so the tool uses Classic and gives you 2400×1800 with a note explaining why.
| Limit | Computer | Phone or tablet |
|---|---|---|
| AI 2× (input image) | up to 1 MP (about 1000×1000) | up to 0.36 MP (about 600×600) |
| AI 4× (input image) | up to 0.25 MP (about 500×500) | up to 0.09 MP (about 300×300) |
| Longest side of the result | up to 8192 px | up to 4096 px |
| Pixels in the result | up to 36 MP | up to 16 MP |
Tips
- AI sharpens edges and detail, but it can't recover detail that was never there, such as a completely blurred face.
- If your image is over the AI limit, crop it to the part you need, then upscale.
- The higher-quality model is noticeably slower, so try the light one first.
- Images with a transparent background keep their transparency.
- For printing, upscale once at 2× or 4×; don't upscale the result a second time.
Your image is processed in your browser and is never uploaded to a server. Only the TensorFlow.js library and the ESRGAN model files are downloaded.
Frequently asked questions
Is this image upscaler free?
Yes. It is completely free, with no account and no watermark.
Is my image uploaded to a server?
No. The model runs in your browser on your device; only the model and library are downloaded from the internet.
What is the difference between AI and classic upscaling?
Classic upscaling calculates new pixels mathematically from their neighbours, which looks smooth but softer. ESRGAN was trained on many images and rebuilds edges and texture, so the result looks closer to a genuinely higher-resolution photo.
Why are there size limits?
AI upscaling needs memory that grows with the image area, and a browser tab only gets a limited amount. Going over the limit can freeze or crash the tab, especially on phones, so mobile devices get lower limits.
What if my image is over the limit?
If it is over the AI limit, it is upscaled with the classic method and you see a note saying so. If the result itself would be too large for the browser, the tool asks you to choose 2× or a smaller image.
How long does it take?
It depends mostly on your device's graphics chip. A small 450×300 image with the light model can finish in seconds on a machine with good graphics, and take a minute or more on a weak one. 4× and the higher-quality model take several times longer, and a progress percentage is shown throughout.
How do I know the result really used AI?
Each result carries a label: Made with AI (ESRGAN) or Classic upscale, not AI (Lanczos-3).
What format is the output?
PNG, so no extra quality is lost on top of the upscale. The file is named after your image plus 2x or 4x.
Does it keep PNG transparency?
Yes. ESRGAN only processes colour, so the transparency channel is enlarged with Lanczos and merged back into the result.
Why did it switch to Classic when I chose AI?
For one of three reasons: the image is over the AI limit for your device, your browser has no WebGL graphics acceleration, or the model could not be downloaded. A message tells you which.
Can I upscale 8×?
No, the tool supports 2× and 4× only. Repeated upscaling lowers quality, so start from the largest original you have.
Which libraries does it use?
UpscalerJS with the esrgan-slim and esrgan-medium models, running on TensorFlow.js. All of them are open source.
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