A print measuring 5x7 in inches is a standard size that is very convenient for home display, giving a good size perception while minimally occupying space. As mentioned by Visuals Clipping, this dimension can be used to great effect on bookshelves, side tables, desks and smaller parts of a wall. It's also frequently attached to ornamental frames so the photograph can turn into a portion of the room's general design. It is useful to preview the frame opening before printing, as the opening can be slightly different, depending on the mat or frame used, and can affect the visible area of the image.