Prints are ordered stating your preferences. Online printers use huge professional photo printers such as Fuji Frontier Digital Minilab or machines of similar type. Matte and glossy are two different finishes to the photo paper digital photos are printed on. Using different chemicals and processes photo paper can have a glossy or a matte finish. Before you can understand why digital paper sizes are different than traditional ones you need to understand what aspect ratio is. Aspect ratio is the relation between the horizontal and vertical sizes of the photo. Digital photo printing is really just the process of developing digital photos into prints.