Ideally they should be 3 by 5, e.g. 1200x720 to be in the exact right proportion. That way they won't be cropped.
Thank you! One question: how can I resize photos for show them properly in youmagine? Have a good day Paolo
Great job. One of those typical things a 3D printer is useful for! I featured the design. Thanks for making YouMagine a cooler place!