Hi, I own a Canon Power Shot S-45. I understand how if one wants to print anything at 8X10 or larger should get a camera that is at least 3 megapixel. Now my question is, how large of a print could I get with my S-45 without losing much quality? The three sizes I'm considering are 8X10, 11X14, and 16X20. I would prefer a 16X20, but I'm not sure if 4 megapixel would do it. Would there be a big difference between 4megapixel and 5megapixel camera at 16X20? Thanks for answering!!