I am a volunteer ofr the local historical society and I thought it would be cool to go out and take current photos in the same location of photos taken 100 yrs ago. I was wondering if there were some sort of app that would allow you to see through the 100 yr old image on the viewfinder of the phone. In other words, I would show up at a location where a previous photo was taken and I would load the previous photo up into the phone and when I turned on the camera, the old photo would be somewhat transparent on the screen, so I could try to see the exact same point where it was taken 100 years ago. I have no idea if there is anything like that, or what it would be called. I''ve searched for hours and have come up with nothing. Any ideas or hacks? And once I got the double photo, it probably isn't too hard to make one or the other more or less transparent, so both images could show up on a final product? What product would do that?