This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
let's say I have a png file and I want to change all the red colors to another color. is it possible? what's the code?
Where are you processing the image? I don't know how to do that in the mobile, but on the server-side you can use Java Advanced Imaging for manipulating the PNG image. Here's my attempt to code a sample using the JAI API (not compiled, no guarantees of any sort):