Most background-remover guides tell you to upload a picture and click a button, which is true and does not help you get a good result. The quality of a cutout depends on how the tool works inside and on what you give it. We wrote this from our own tool's engineering notes: what the model actually sees, what happens to the edges, what size file you get back and what the limits are. It also covers product photos and phone use, the two cases most people ask about.
What happens to your photo
The Background Remover runs on our server, because the model is too heavy for a browser. The steps, in order:
- The model looks at a 512-pixel copy of your image and produces a matte, a grayscale map of how much of each pixel belongs to the subject.
- The matte is cleaned with a rescale that pushes near-transparent pixels to fully transparent and near-solid to fully solid, while keeping the soft pixels in between. It deliberately does not cut at a hard threshold, because a threshold turns every strand of hair and every anti-aliased edge into a jagged step.
- The matte is scaled up to your photo's exact size and applied to the original, untouched pixels. Nothing about your colours is resampled.
- Edge pixels are decontaminated. A pixel on the edge of a subject contains some of the old background. Making it 40% transparent would leave 40% of that old background smeared around the outline, which is the halo you see when a cutout is dropped onto a new colour. The tool estimates what the subject alone looked like there and pulls those pixels towards it.
One consequence matters in practice: because the model works at 512 px, very fine detail such as single hairs is described coarsely and then scaled up. The decontamination and the soft matte hide most of that, but a close look at flyaway hair against a busy background will show where the limits are.
The file you get back
You receive a PNG with an alpha channel, at your original dimensions. PNG is lossless, so these files are large. In our engineering measurement, a 6000 × 4000 cutout came to 19.9 MB at the default compression. A photo 1600 pixels wide is a tiny fraction of that. The pixel count is what drives it, so the reliable way to a small file is to resize the photo before removing the background if you will only use it at web size.
After the cutout, pick the format by where it is going. A JPG cannot hold the transparent area (it fills it with a solid colour). In our format tests, converting a transparent PNG to WebP kept the transparency and made the file 29% smaller. Our format guide has the details, and the compression guide covers sizing for the web.
Limits to know before you upload
| Limit | What it means |
|---|---|
| 3 MB per photo | The page refuses larger files before uploading. Compress or resize first. |
| Queue | Jobs are processed in turn, so it can take longer when the tool is busy, and there is a per-visitor hourly limit. |
| Retention | Your upload is deleted within 1 hour and the finished cutout within 6 hours (see the privacy policy). |
| One subject per photo | The tool picks the main subject automatically; there is no control for choosing which object to keep. |
We have not systematically tested difficult material such as fur, thin wire, glass, or blonde hair against a white wall. Expect to check the edges of anything like that, and to touch up the result in an editor if the picture matters.
How to shoot a photo that cuts out cleanly
- Separate subject and background by colour and brightness. This is the single biggest factor, because the model is deciding where the subject ends.
- Light the subject evenly. Hard shadows on the background look like part of the subject, and shadows on the subject look like background.
- Keep the subject whole and in frame. Cropped edges and objects held in front of it confuse the outline.
- Use enough resolution, not too much. About 1500 to 3000 pixels on the long side is plenty and keeps you under the 3 MB limit.
Product photos for a shop
Shoot the product on a plain, lighter or darker surface than the product itself, with soft light from the side so the edges are clear. After the cutout, place it on a plain white or coloured background, which most marketplaces expect, but check each marketplace's own image rules because they differ and change. Add a soft contact shadow under the product when you place it on white. A cutout with no shadow looks as if it floats, even when the edges are perfect. If you list the same product on several sites, keep the transparent PNG as your master and export a JPG or WebP for each.
Removing a background on a phone
The tool works in a mobile browser such as Safari, Chrome or Samsung Internet; there is nothing to install. Open it, choose a photo from your gallery (it must be under 3 MB, which many recent phone photos exceed, so reduce it with the Image Compressor first), wait for the result and save the PNG. Two practical notes. Some gallery apps display a transparent PNG with a black or white background even though the transparency is intact, so judge the file by placing it in a design or chat app rather than by the gallery preview. And a transparent PNG on a phone connection can be large, so save only what you need.
Step by step
- Resize or compress the photo to under 3 MB with the Image Compressor if needed.
- Open the Background Remover and add the photo.
- Wait for the cutout, then use the before and after comparison to check the edges, especially hair and corners.
- Download the PNG. For a smaller file with transparency, convert it to WebP with the Image Converter.
- Need a plain-colour or passport-style background? Use the Passport Photo Maker or place the PNG on a coloured layer in any editor.
What this guide does not claim
We describe how our own tool works and the limits we know about. We have not benchmarked it against other background removers, and we have not published a test set, so we make no comparison claims. Processing time varies with image size and how busy the server is, so we do not quote a number.
