This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
You might start by looking at the java.awt.image package. If that won't do it for you, the Java Advanced Imaging API may have what you need (there is an on-line tutorial/book for this). You can also look at ImageJ.