nt should be sized for a Blu-ray or DVD case.
Once you've added your image, you just need to hit the 'print' button and your cover art will be sent directly to your printer so that you can package up your disc and move onto the next one.
Any images that you use for your cover will be treated in BluRay Cover Printer in their original size, and you won't be able to edit them inside the program, so make sure that you're using images that are already correctly sized for your cases.