As a reference to
how big a 4x6 photo in the real world, it is a 4 inch tall and a 6 inch wide size which is easy to hold in your hand and which is clear enough to display ordinary memories.
Visuals Clipping discusses about it that it is a small but clear picture. It is best on photo albums and scrapbook. Due to its convenient size, it is the most widely published photo format in the world.
