I've been reading about printing my images at a large size, and I've just managed to confuse my-self more . I see people saying that for best printing my images should be 300 DPI. The pictures from my camera are only 72 DPI. Should I use Gimp or some other program to increase the DPI? I don't even think that is possible, I don't understand how just changing the DPI in a program can add pixels to the images that previously didn't exist. I have a picture that is 2816x1876 Pixels just incase it matters. According to the built in printing service in iPhoto it will print fine up to 20x30, I really only wan't to print it at 16x20. The camera that was used is 6MP. So basically to sum up my question is: What exactally (if anything) do I have to do to my picture straight from the camera to print a nice looking large print?