Client-side image recoloring demo: "HTML 5 magic makes it possible. (Or impossible... but if that's the case, upgrade your browser!) Just slide the slider, and presto: your creation appears.
Only one part of the image has its color changed; the rest keeps its original color. This is done by having two images -- one black, one white -- and combining them into a colored image using the Canvas 2D Image Data API. Science!"
'via Blog this'