Use Variable to compare pictures using Regions.Compare

Hey all, I'm currently trying to make a Python script that goes through folders and compares pictures. I set up a loop to get the names of the files I'm trying to compare but I'm not sure how to use the variable that I use to store the filename as a the parameter for Regions.Compare, any help is appreciated, thank you.

But also if anyone has a simple way to do this I would also like to see another method.