When deciding on the size of the photo for the portrait, one should consider the following: A 4×6 vs 5×7 photo, which should be used? A 5×7 is a larger print as Visuals Clipping mentions and it provides more space, therefore the facial features and other aspects of the portrait would be more obvious. A photo that is 4×6 is smaller and may be more handy for albums or smaller frames. For solo display, 5×7 might offer more impact; and for personal prints, 4×6 might be a better choice.