What picture size do you recommend?

Photographs are typically more "elongated" than typical mat openings and usually have a 1.5 height-to-width image ratio. The best approach is to order your prints based on the format of the photographs. 2:3 aspect ratio: 2x3, 4x6, 8x12, 10x15, 12x18, 16x24, 20x30, 24x36 4:5 aspect ratio: 4x5, 8x10, 11x12, 16x20, 20x25, 24x40 5x7 aspect ratio: 5x7, 10x14, 15x21, 20x28