Admittedly, it's still hit or miss. I spend quite a bit of time on the 'net, probably too much time, and I lurk around every corner. (I'm a cat, so I'm curious about everything.) As a TG, I also surf the world for lingerie ideas and so forth, so I cut a pretty big swath of the 'net.
Sometimes, I will type a short description of the photo into Google--that, again, is hit or miss.
I've also played with photoshop, so I'm getting better at discovering air brushing, cut-and-paste cocks, enlarging breasts, etc.
By looking at the source code, one can see if an EROS ad was created since its big pagename change to numbers. But, that will only work for so long.
I know you've done this, but even I sometimes forget to search our own board. I will also search with the TER name feature in Reviews, and even with other info if it's available.
Another thing: When an ad has expired, say on CL or Backpage, many times there will be a "Cached" page (the link is below the Google description).
I'm very passionate about exposing fake providers because, in my mind, they are stealing money from the real ones. Unfortunately, fake providers have no ethics, so they don't care.
I'd search the board for "fake" with the "exact word" feature. Even so, it's still hit or miss.
When I first started on this board and even when I first became a mod, my knowledge of fake pics was quite inexperienced. But, in time, and from lots of research, I'm getting better.
Oh yeah, another thing I've started doing: When I find a fake, I do a screen capture of the entire page and save it for future reference. Firefox has a great add-on called "Screengrab" that is terrific.