Logo (optional)
Logo will be displayed in the top area of the screen, just above the windows. As an alternative the logo can be designed as part of the background image. Size is optional.
Size of images in windows
Adjusts automatically: Minimum 700 x 400 pixels for the best result
Size of background images in windows
Prize background: 760 x 160 pixel
Window background: 760 x 600 pixel (Minimum in terms of content)
Size of background images
Designing your own theme requires uploading 3 background images.
The image sizes are also specified under Design > Customize > Calendar frontpage in Advent Calendar.
Background image horizontal: 1680 x 1050 pixels (PC/Mac)
Background image vertical 1050 x 1680 pixels (Mobile/iPad)