I have been wanting to do something like shown in the link below. Merging 2 photos into one. Using an Old Historic photo overlaid on a new current photo. Putting each into its own layer, I need to manipulate the second layer to match points in the first layer. Since the photos were taken with different lenses and there is no knowledge of what that may be, the Second layer needs to be distorted to match the first. I have read of Point registration in mapping software and I would imagine it exists within graphic software also. I have looked at the power stretch plugin in and something like that only in multiple points. matching building corners in one to another, maybe match 5 to 100 points and the image would distort to match those points.
Anything Paint.net has in that area, or a direction I may look to do this type of work?
http://www.boredpanda.com/know-where-you-stand-historic-moments-blended-into-present/
Thanks
Chris