lucy24 - 1:16 am on Feb 15, 2013 (gmt 0)
Ooh, that's kind of ingenious. It's based on going one step back from what most fixes use. You have to give g### image search a different file in the first place-- that is, a file with a different URL-- because that is the only sure way to tell if someone is looking at a search result. This part, of course, can't be done retroactively; you have to work it in slowly as they re-crawl your site.
There's one big risk though, and the post itself points it out:
just like other solutions it's up to Google to inte[r]pret it as cloaking and ban at their will
So it will only work as long as the googlebot doesn't realize that nobody else is getting redirected. It has to be a redirect, not a rewrite, because the whole point is to create a different URL.*
Now, why is this part of the discussion here rather than in the ongoing Google-Image-Search thread?
* You could theoretically do it as a rewrite at the original URL-- but only if you had some supplementary php business that cross-checked the filesize down to the last byte to determine whether you're dealing with the real file or the search engine's version.