You are able to change the orientation of photos on products that do not have any additional text or graphical elements! In order to do so, just locate the circular arrow icon within your product customization window.
This will allow you to switch between orientations on your print!
If a products has additional elements such as customizable text or background themes, you are able to crop the photo to your liking, but you will not be able to rotate the image due to these products having a set orientation to make the final product as visually appealing as possible!