Quick Photopass Question Saving as 4x6

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I'm in the process of editing and adding borders/signatures to my Photopass photos. It says that any unedited images will be burned on the cd in a 4x6 aspect ratio. Edited photos (ones with borders and signatures) will be burned on the cd in a 5x7 aspect ratio, unless you save them as 4x6 when you make your edits. I am concerned that portions of my borders will be cut off when I print them as 4x6, so I want to change it on the photopass site when I save. However, the only place I see to indicate size is under the "order prints" section where it says "product type". Am I missing something? Can someone please tell me how to save my edited photos in 4x6 format? Thanks!