Picture Frame Questions

[RweTHEREyet]

I have found several images that were set up to be picture frames. Please don't laugh at my question, but just how do you use them? Do you insert a picture of your own in the frame area and then print it as one picture or do you print the mat out on something like cardstock and use it as the frame? I have not seen any of these as a completed project and am just curious.

 

[MrsHeg]

Insert a picture of your own and print them together.