What is the criteria for blowing up a digital photograph to a 20 x 30 poster? I searched and couldn't find a definitive answer. Maybe I didn't have the right keywords in my search. Is it a function of: 1.) Resolution (3456 x 2304)? 2.) DPI (I assume between 240 - 300 is an acceptable range)? 3.) megapixel capability (8 mp? more?) ? 4.) all of the above? If more than 8mp is required, how much more? Mods: seemed like a beginner's kind of question, but go ahead and move it if its more apporpriate in another forum.