Java Programming

Hello,
I'm working on an application that load images (any format) and display them in a panel. User can zoom those images that are usally around 5MB in their original size. The application ends up having heap space problems. I have already increased the heap size but still have this problem sometimes.
I've been looking around methods that I can be used to reduce the images up to a certain limit size but I haven't found anything that can be used with different image formats.

Can anyone give me a clue on how to perform this?

Thank you!