I have a blog and it seems that google has indexed the thumbnails from my galleries as well as the actual photos. Is there a way to have google not index specific file sizes? Maybe putting that in Robots.txt? Disallow: *150x150.jpg Would something like this work?
Probably it won't, you can specify the exact image to not to get indexed, but with size it seems hard. Google got a help file on this - https://support.google.com/webmasters/answer/35308?hl=en
I think @evildon is right..You can block the individual images, but doing it by size might be a little tough. Here's another article you can checkout: https://support.google.com/webmasters/answer/79892
Don't know if this would work, but couldn't you technically put all the thumbs or certain size images in certain directory, then create a disallow in robots.txt for that folder? Not sure if this is a workable solution, haven't tried it. Above solutions should work too though!
Yup, putting all those files in a folder and then disallowing that folder from Google indexing would work.. Here is the help file for that - https://support.google.com/webmasters/answer/156449?hl=en