Ansel Adams "photoshopped" all his pictures...not like we do it now of course, but manipulating photos has been ongoing since the invention of photography...that being said, I'd say a vast majority of, as they now call them, "images", are manipulated to some degree. I will admit, I too, use photoshop, but mostly to crop...In most cases, it isn't that hard to figure out which have "had work done"...I see people just taking pictures by the bucket full and just take care of them later...I'm somewhat old school on this and I never delete a picture I have taken, unless it is blurry or badly exposed. You never know when that picture you took may have relevance in your life...