How it works
The cut-out is made by MODNet, an open-source AI model for portrait matting published by researchers at City University of Hong Kong and SenseTime. "Matting" means it does not just draw a hard outline: for every pixel it estimates how much belongs to the person, from 0 (background) to 100% (person). Partly covered pixels, such as wisps of hair, get in-between values, which is why the edges look natural instead of cut out with scissors.
The model runs inside your browser with ONNX Runtime Web, Microsoft's engine for running AI models in WebAssembly. Both the model file and the runtime are served from this site, and the work happens in a background thread so the page stays responsive.
Your photo → shrink a copy to about 512 px on the short side → MODNet estimates the matte → enlarge the matte to the full photo size → use it as the alpha channel (or to blend onto your color) → PNG
Worked example
You drop a 4032 × 3024 phone photo of a friend standing in a park. The tool feeds MODNet a 672 × 512 copy (the short side scaled to 512, each side rounded to a multiple of 32, which the model needs). MODNet returns a 672 × 512 matte in a few seconds on a laptop, longer on a phone. That matte is enlarged with bilinear smoothing to 4032 × 3024 and applied to your original pixels, so the download is a 4032 × 3024 PNG of your friend with a transparent background. Choose Solid color and White, and the same picture comes out on plain white instead.
What it is good and bad at
| Photo | What to expect |
|---|---|
| One person, head and shoulders or half body | The best case. Clean outline, natural hair edges. |
| Full-length shot or a small group | Usually good. Thin gaps between arms and body may keep a little background. |
| Person against a background of similar color | Edges may wander where the two blend together. |
| Product, pet, car or logo with no person | Unreliable. The model was trained on people, so it may remove the object too. |
| Very large photo (above about 16.7 megapixels) | Scaled down to that size so phones can handle it. |
Privacy
Nothing you choose is uploaded. The first time you pick a photo, the page downloads the 25 MB model and the engine that runs it from this site, not from a third party; after that your browser reuses its saved copies. The photo itself is decoded, processed and saved as a PNG on your device. The PNG is a fresh image, so it carries no EXIF data such as GPS location or camera details. Close the tab and everything is gone.
Tips for a cleaner cut-out
- Use a sharp, well-lit photo where the person stands out from what is behind them.
- Keep the whole head in the frame. Cropped heads and hands confuse the outline.
- For a white background on a shop or profile photo, choose Solid color and White, then keep the Edge on Natural.
- For stickers or overlays on busy pictures, a slightly crisper edge hides color fringes from the old background.
Questions people ask
Is my photo uploaded to a server?
No. The photo is opened, cut out and saved inside your browser tab. The only downloads are the AI model (about 25 MB) and the engine that runs it, fetched from this site the first time you use the tool. Your browser keeps a copy, so later visits skip the wait. You can switch off Wi-Fi after the model has loaded and the tool still works.
Does it work on products, pets or cars?
Not reliably. The model, MODNet, was trained to separate people from their backgrounds. On a person it usually finds the body, clothes and hair. On an object with no person in it, it often removes too much or too little, and with no person at all it may erase almost everything. The tool warns you when it finds almost no subject.
Is the cut-out full resolution?
Yes. The output PNG has the same width and height as your photo (very large photos over about 16.7 megapixels are scaled to that limit so phones can handle them). The model judges the outline at roughly 512 pixels on the short side, and that outline is then smoothly enlarged to full size, so the colors are your original pixels but very fine detail such as single strands of hair can look softer than in the photo.
How do I put a white or colored background behind the person?
After the cut-out appears, choose "Solid color" under Background and pick a color, or press White. The preview updates immediately and the download is a PNG with that color filled in. Choose "Transparent" to get a PNG with a see-through background for layering in another app.
Why are the edges a little see-through, and can I make them sharper?
MODNet produces a soft matte, which keeps hair and blurred edges looking natural. If you are placing the person on a busy background and see a halo, move the Edge slider toward Crisp. That makes partly transparent pixels either solid or fully clear. At Crisp the edge is a hard cut, which suits logos and stickers but can look jagged on hair.
Can I use this for passport or ID photos?
Usually not. The US State Department rejects passport photos that have been digitally altered, and replacing the background counts. Take the photo against a plain white or off-white wall instead, then size it with our passport photo maker.