This is the sequence part of this question: Combining 2 Images overlayed
so the problem is: if the image size is too big - it\'ll got an exception (out of memory exc
The only way I can think of to handle this would be to divide the images up into pieces so you don't have to keep everything in memory at once. If you don't want to keep bmp1 you can draw bmp2 directly on top of it rather then creating a new bitmap as well, though I'm not sure if this is what you're after.
I think you have no choice, but to rescale the bitmaps in a lower size...