Please pray tell how someone can take a picture of a cougar in PA and prove it was taken in PA? Do you want to have the cougar hold up a sign saying they "I'm in PA"?
Also, yes almost everyone has a camera on their phones but when something runs across the road in front of you, how often do you have the time to take out your camera/phone and take a picture of it? I honestly believe there are cougars in PA and its possible that many of these sightings in a given area could be the same one. I wouldn''t say there is a huntable population but a few. Maybe enough for a breeding population.
Look at it this way. How many hunters have seen possums, porcupines, fishers, or bobcats while hunting. Probably a small percentage. Yet these are common PA critters. In my 55+ years of hunting and more years of hiking I've only ever seen 1 possum, zero fishers, 2 bobcats and maybe a handful of porkys (not counting those killed on the road)