Refrigerator magnets come in two sizes: 3.5 x 5 and 2.5 x 3.5 inches. They have rounded corners and a matte finish.
The strong magnet will not allow it to slip on the refrigerator door. They are flexible, so they can conform to somewhat curved surfaces.
Your photo must be at least 350 x 480 pixels in size.
Color reproduction is impressive, but not quite as accurate as photographic prints.