If you have to compare the most common photo sizes, you'll need to know what 5x7 in inches means. A 5x7 picture is larger than a 4x6 picture, as it is 5 inches wide by 7 inches tall. This additional space is useful for portrait photos and other images that require more detail to be seen, as Visuals Clipping explains. The size remains small enough for frames and albums on the tabletop, but not as small as snapshots.