Googlebot-Image indexing hundreds of useless thumbs and a few pics

[flapane]

If I check the gallery indexed photos in Google Images ( site:flapane DOT com SLASH gallery ), I notice that there are just a few pics (normal_$nameofthefile.jpg) and hundreds of useless thumbs (thumb_$nameofthefile.jpg).
I wonder why Googlebot-Image indexed only a few images, and why it indexed a lot of small thumbnails. I have no robots.txt rules for Googlebot-Image, but I wonder if I'd better adding:

Code Select Expand

User-Agent: Googlebot-Image
Disallow: /gallery/thumbnails.php?*

As a sidenote, my robots.txt already contains:

Code Select Expand

User-Agent: *
Allow: /
Disallow: /gallery/addfav.php?*
Disallow: /gallery/login.php?*
Disallow: /gallery/thumbnails.php?album=*slideshow

[flapane]

I've just put this in robots.txt.

Code Select Expand

User-agent: Googlebot-Image
Disallow: /gallery/albums/*/thumb_*.jpg$
I'll check the results in the next days/weeks.
It seems to work, as far as GWT is concerned.

[flapane]

Uhm, it looks like after three weeks the thumbs are all still there. In theory, the trick should work.
It's strange, because Google bots are usually waaaay faster than Bing ones.