I'm writting an application that takes a screenshot and allows the user to draw on it. The problem is that when I look at the memory usage, every time I draw a line or something it uses up 10 more MB and eventually uses up 1.5GB of memory and then for a reason I'm not sure of, it drops down to about 250MB and keeps doing that. My guess is that it has something to do with the Bitmaps I'm making. I have a bitmap that updates eveytime a line is drawn and 3 more bitmaps to contain the three previous images so that the user can undo their work. This works without a problem except that it uses up a lot of memory. Is there any way I could release the memory being used so that it doesn't keep building up to 1.5GB of memory usage?

Thanks in advance.