The following instructions tell you how to change a colour in to the transparent colour. It can also effectively be used to swap a colour.

This is a small How-To on changing the background color of a image to transparent using open source GIMP Image editing application. The idea is to add alpha channel, select by color and cut it.

1. Open the Image in GIMP
2. Navigate Layer -> Transparency -> Add Alpha Channel.
3. Navigate Select -> By Color
4. Mouse click on background color of image
5. Navigate Edit -> Cut
6. Save it in format of your choice (Warning: JPEG does not support transparency, so opted for PNG format)