Pick a color. Pick another.

No. The pixel-by-pixel color swap runs in your browser. Your photo never touches our servers — we don't run an image pipeline at all.

Turn it on, then drag across the photo — the source colour follows your finger. It samples a 3×3 patch of the original file at full resolution, not the scaled preview: reading a pixel off a downscaled preview returns an average of several source pixels, which on a strong downscale can be a colour that appears nowhere in the photo.

It moves every matched pixel by the same step in OkLab rather than painting a flat fill, so each one keeps its own offset from the colour you sampled — folds stay folds, highlights stay highlights, and the weave of a fabric survives. Turn it off and every match becomes one flat colour, which is what you want for a graphic poster.

Turn on Show selection: the matched area is painted magenta so you can see exactly what the tolerance catches before you commit. Then move tolerance until the mask covers what you meant. It is quoted as ΔE in OkLab, where 1 is the smallest difference an eye can see and 10 is clearly another colour, so the number means the same thing on any photo.

Pixel-distance matching works best on solid-color regions. Patterned fabrics with multiple colors per inch are harder — you can run the swap multiple times (once per pattern color) to recolor each separately. Or use a more advanced editor with object-aware selection.

A real green shirt runs from deep shadow green to a near-white highlight, which is a wide span in any colour space. Raise the tolerance until the selection mask covers the whole garment. If background foliage starts coming along, lower it again and push edge softness up so the fringe fades instead of cutting.