The illustrations are of great diversity. Therefore it would be good if you could give a reference model. Illustration can be a logo, text shorter or longer (up to 10 words), different image of medium or high complexity, in different combinations that you like them. The image may be related to the front and back.
You will get the project file in PNG, JPEG, SVG, or another that you need. The illustration is transparent format having from 1 to 4 colors.
I guarantee the quality and uniqueness of the project. The illustration is delivered in 300 dpi.
You can check for other options in My Gig Estras.