The cover images need to be the following size:
Mini: 4.1" x 5.6" (827x1118 pixels)
Square: 5.8" x 5.6" (1157x1118 pixels)
Wide: 8.3" x 5.6" (1654x1118 pixels)
Classic (A5): 5.8" x 8.1" (1157x1614 pixels)
Big (A4): 8.2" x 11.6" (1654x2339 pixels)
Wall Planner: 12.0" x 12.0" (2362x2362 pixels)
We want your printed picture to be as close as possible to the preview on our website but, occasionally, the print version can differ by a few millimeters. For that reason, make sure to keep important bits at a safe distance from the edge!