Picking a size
Hold a sheet of paper (8.5×11) against the wall where the print will go. An 8×10 is just smaller than that sheet. A 16×20 is about four sheets in a square. A 24×36 is close to a poster.
A general rule: over a sofa, bed or console, the print (or a group of prints) should cover about two-thirds of the furniture's width. For a hallway or desk, 8×10 and 11×14 hold their own.
Shape matters
8×10 and 16×20 are the same shape (4:5). 20×30 and 24×36 are 2:3, the shape most cameras shoot. Phone photos are usually 3:4, so a little gets trimmed on any of these. Our upload checker tells you how much.