Currently, I have a good image, which I originally obtain from web.

enter image description here

Since I have 2 different themes for my app. I need a same image, but with different foreground color. I use "bucket fill", to perform color replacement.

enter image description here

However, such technique doesn't handle anti-alias well. In fact, you will get a zig-zag result, when using this simple technique to perform color replacement. This is what it looks like, when I zoom-in to the "eye" region.

enter image description here

The "zig-zag" effect is obvious, when the app is deployed to a low DPI android device.

App's outlook when using original image

enter image description here

App's outlook when using color replaced image (Zig-zag effect seen)

enter image description here

May I know what are some proper ways to perform color replacement?

  • IDK abut paint.net but in PS you would go to blending and color overlay for a proper color change.
    – Alin
    Oct 2, 2016 at 19:36
  • 1
    Rule of thumb, if you find yourself using paintbucket then your doing something wrong. I dont have paint dot net installed but can you select the transparency mask?
    – joojaa
    Oct 3, 2016 at 9:02
  • @joojaa Nope. I check the Layers windows, I saw there is only 1 Layer named background. I do have a more advanced image editing tool called GIMP. I try to follow superuser.com/a/718521 but the "Color to Alpha" is disabled. Oct 3, 2016 at 23:40
  • Am too tired to write this as an answer right now, but get Gray to Alpha and you can remove perfectly white/black backgrounds from grayscale drawings with 100% precision, then go about coloring the foreground as desired.
    – kettlecrab
    Aug 6, 2017 at 8:59

1 Answer 1


Don't use the bucket tool. From your original image:

Go to adjustments in the top menu and then curves

enter image description here

Having it set to luminosity will allow you to control the brightness and contrast by dragging the curve about.

Changing to RGB will allow you to control the amount of each colour in the layer.

As you move them you should see your image update and the anti aliasing remain in place.

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