I guess the modifications I did to it (while using a work PC... yeah, I know, but I wasn't on the clock) did the trick. Now it works just fine. I was saving images using myBitmap.Save(string filename) when I should have been using myBitmap.Save(string filename, ImageFormat.Bmp). I don't know why that would make a difference, but it did. It still doesn't answer the question of why it wasn't displaying images that were originally bitmaps, but, hey, it works now. Thanks anyway!
-Daniel Typing too fast fro my owngood