Replace a colour in an image — swap one colour for another

How to use Image Color Replace

1. Choose one or more images.
2. Set Colour to replace. The default is white, #ffffff.
3. Set New colour. The default is green, #22c55e.
4. Set Tolerance (0–60%), how far a shade may be from the chosen colour and still be fully replaced. The default is 12%.
5. Set Soft edge (0–30%), a band beyond the tolerance where pixels are only partly changed. The default is 4%.
6. Press Apply. A note says how many pixels, and what share of the image, were fully replaced.

What it does and when to use it

It is a quick colour swap for flat images: change a white background to a brand colour, recolour a logo or icon, turn a red button blue, or fix a wrong colour in a chart or diagram. It works best where the colour is even, such as graphics, scans and product shots on a plain backdrop.

Find the exact colour first with the image colour picker. To change all colours at once by the same amount, use Image Hue Rotate. To cut out a busy photo background instead of recolouring it, use the background remover.

How it works

The tool measures how far each pixel is from the target colour as a straight-line distance in RGB space:

distance = √((R − R₀)² + (G − G₀)² + (B − B₀)²)

The largest possible distance, from black to white, is √3 × 255 ≈ 441.7. Tolerance and Soft edge are percentages of that.

• Pixels within the tolerance are fully replaced by the new colour.
• Pixels in the soft-edge band are blended: the further out, the less they change.
• All other pixels are untouched, and transparency is kept.

The soft edge stops a hard, jagged outline around shapes that had anti-aliased edges. Everything runs in a background worker on your device; nothing is uploaded.

Worked examples

These values come from the tool’s own function, with the defaults: white to #22c55e, tolerance 12% (distance 53.0) and soft edge 4% (up to distance 70.7).

• Pure white (255, 255, 255). Distance 0, so it becomes (34, 197, 94), the new green.
• Off-white paper (240, 240, 240). Distance about 26, inside the tolerance, so it also becomes pure green and is counted as replaced.
• Light grey (220, 220, 220). Distance about 60.6, inside the soft-edge band, so it is only partly changed, to (114, 207, 148), a pale green.
• Red to blue, tolerance 20%. With #ff0000 as the colour to replace and #0000ff as the new colour, a pure red pixel becomes pure blue, while an orange-brown (200, 100, 50) is too far away and stays the same.

Limits and tips

• Shading inside an object is not kept. A replaced area becomes one flat colour, so a shaded red ball turns into a flat blue disc where it was within tolerance.
• For photos with soft lighting, a hue shift often looks more natural.
• Keep PNG for graphics so the new edges stay clean.