Does this work on photos with detailed backgrounds?

Not well. This is a colour-key remover: it removes pixels similar to the one you pick, which is ideal for a solid or near-solid background and poor for a busy street scene. For complex subjects you need an AI segmentation tool, which necessarily runs on a server.

Why are there rough edges around my subject?

Raise the tolerance slightly to catch the anti-aliased pixels at the boundary, which are a blend of subject and background. If raising it starts eating the subject, the background is too close in colour to the edges and this technique has reached its limit.

What format do I get back?

PNG, always — it is the format that keeps a true alpha channel. Exporting as JPG would fill the transparency back in with white, which defeats the purpose.

Background Remover

Click a colour in the image and every pixel close to it becomes transparent, with a tolerance slider to control how close counts. Export as a PNG with a real alpha channel. It works best on flat, even backgrounds — product shots on white, logos, screenshots — and runs entirely in your browser.

Runs in your browser — nothing is uploaded

Questions

Does this work on photos with detailed backgrounds?: Not well. This is a colour-key remover: it removes pixels similar to the one you pick, which is ideal for a solid or near-solid background and poor for a busy street scene. For complex subjects you need an AI segmentation tool, which necessarily runs on a server.
Why are there rough edges around my subject?: Raise the tolerance slightly to catch the anti-aliased pixels at the boundary, which are a blend of subject and background. If raising it starts eating the subject, the background is too close in colour to the edges and this technique has reached its limit.
What format do I get back?: PNG, always — it is the format that keeps a true alpha channel. Exporting as JPG would fill the transparency back in with white, which defeats the purpose.