Customized Postcards Let our skilled design team help you create a custom postcard, or print art you provide to us. Postcards can be produced in an uncoated, matte or gloss finish, in a multitude of sizes. The most common sizes are 4” x 6”, 5” x 7”, 5.5” x 8.5”, 6 x 9”, and 6 x 11”. Our staff can also assist you in creating a successful mailing campaign by developing a mailing list for your target audience.