I'm creating a clone of Bomberman.

I've fixed up a bunch of sprites for representing the characters walk-animation.

Here is the one for the walking-down head..

Now to my question.

I don't want to create a sprite for each color a character can have.
So how do i change the color of the pixels in this image to lets say green, blue or red..
I want to keep the alpha values of the image ofcourse.