Margin trimmer

Cuts the empty margin off every side and leaves the picture. A transparent margin is unambiguous; a coloured one is a judgement — the tool calls a colour the border only when at least two corners agree on it, then removes whole rows and columns of that colour. That judgement can be wrong where the picture itself fades into the border, so the preview dims exactly what will go before you download.

How to use it

Choose PNG, JPEG, or WebP images. Up to 5 at a time and 20MB each.
Look at the preview: the dimmed area is what will be cut, and the result size is shown above it.
If a faint border survives, raise the tolerance. If the picture is being cut into, lower it.
Set a margin to keep if you do not want the picture flush against the edge, then download.

Good to know

A PNG is cut without touching the pixels that remain. JPEG and WebP have to be encoded again, which costs a little quality.
Only whole rows and columns are removed. A margin with a stray mark in it — a scanner speck, a watermark — stops at that mark.
A border counts as one only when at least two corners share its colour, so a photograph that runs to every edge is left alone.

Common questions

The background is removed but the canvas is still large.

Removing a background makes it transparent without changing the canvas. Run the result of the background remover through here to cut the canvas down to the picture.

Is this the same as resizing?

No. Resizing recomputes every pixel to fit new dimensions; trimming discards rows and columns and leaves the rest as they were. What resizing does to a picture is in Resizing images.