Starting Problems: Returning manipulated images

follwing task :
i have a method which gets an image as param and shall return it translucent.
im not very familiar with the possibilities of swing-classes so the only way of getting an image translucent is:


AlphaComposite alpha = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f);
g2D.setComposite(alpha);

but as you can see this method doesnt help me. i really need to create a whole new image which has changed alpha-values.

but perhaps you have a better idea: my target is to have a little helper class, which is able to fade in/out my sprites.
so instead of creating memory-wasting animation-strips i want them to be created dynamically.