- Which mode should I use?
- Start with Fast. If edges look rough, especially around hair or fuzzy outlines, switch to Precise; it uses a far larger model that was trained for exactly those cases.
- Why is the Precise model 170 MB?
- That is the size of the neural network's weights. It downloads once, your browser keeps it, and every later use starts instantly. Nothing about your images is sent anywhere.
- What do I get as output?
- A PNG with a real alpha channel at up to the original resolution. You can place it on any background in any editor, or feed it straight into a design tool.
- Why did a solid color appear instead of transparency?
- Some apps flatten PNGs on import. The file itself is transparent; check it in an editor that shows a checkerboard behind transparent areas.
- Which models does this use?
- Fast is U2Net-p and Precise is DIS (isnet-general-use), both open models under the Apache 2.0 license, running via onnxruntime in your browser.