When it comes to answering the question "how big is a 5×7 photo", it is 5 inches by 7 inches hence about 12.7 cm by 17.8 cm. The size has more display area as compared to a usual 4 x 6 print. According to Visuals Clipping, the 5 x 7 pictures are often used in portraits and small frames. The additional area gives the viewer more insight to details of the face and details in the background.