Image color replacer
Click a color in the picture, choose the color you want instead and set how close a color must be to count as the same. The preview updates as you move the sliders and the result is saved as a PNG. The file stays on your device.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose a picture. The color of its top-left pixel is selected first.
- Click the color you want to replace, or use the color box.
- Choose the new color and adjust Tolerance.
- Press Download PNG. The full-size picture is processed, not the preview.
How it works
For each pixel the distance to the chosen color is measured as the square root of the sum of the squared differences of red, green and blue. If it is within the tolerance, the pixel is changed. In soft mode the pixel moves toward the new color by 1 minus distance divided by the limit. For example, with black replaced by red at 50 % tolerance (limit about 220.8), a pixel (100, 0, 0) is 100 away, moves 55 % of the way and gets a red value of 185.
Worked example
To turn a white background of a logo into light blue, click the white, choose light blue and set the tolerance around 10 to 20 % so the slightly off-white pixels near the edge are included.
Tips
- Start with a low tolerance and raise it until the whole area changes.
- For a cut-out with a transparent background, use the background remover instead.
- Photos with a lot of noise may need a higher tolerance than flat graphics.
Frequently asked questions
How does the tolerance work?
Colors are compared by their straight-line distance in RGB. The tolerance is a percentage of the longest possible distance (black to white, about 441.7). At 0 only the exact color matches, at 100 every color does.
What do soft edges do?
Without them every matching pixel becomes the new color. With them a pixel moves toward the new color in proportion to how close it was, so anti-aliased edges and gradients blend instead of leaving a rim of the old color.
Why is the replacement not perfect on photos?
A photo has many slightly different shades where a flat color looks uniform. Raise the tolerance to catch more shades. Shading is not kept, so a large tolerance gives a flat patch of the new color.
Is transparency kept?
Yes. The alpha value of every pixel is left alone, and fully transparent pixels are skipped.