common printing sizes for book covers are:

1" x 1.5" thumbnail - use on general tracker spreads, challenge picks, etc

1.5" x 2" medium - use for favorite featured covers or thumbnail backgrounds/frames or medium size book covers

2" x 3" large - use for book review pages or highlights

Our free canva templates allow you to easily drag and drop book cover images and backgrounds into the "frames".

I like to add clipart or border images in the white space to get the most out of each sticker sheet and then cut those out with scissors.