thrillho - the bot that Google uses identifies itself as
Googlebot-Image - you can prevent it from indexing your images in the robots.txt file by adding this to it:
User-agent: Googlebot-Image
Disallow: /
However I have only had good returns from the image search feature of Google
- sure there's plenty of people looking for free pics, but then there sure are a lot going to our sites for the same thing
The referrer in your logs would look like this:
"GET /drew-barrymore.html HTTP/1.1" 200 12966 "http://images.google.com/imgres?imgurl=www.celebrity-nude-photos.com/pics/3288.jpg&imgrefurl=http://www.celebrity-nude-photos.com/drew-barrymore.html&h=542&w=600&sz=66&tbnid=i30RCXcUfxoJ:&tbnh=120&tbnw=132&prev=/images%3Fq%3Dcelebrity%2Bnude%26svnum%3D100%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26newwindow%3D1%26safe%3Doff" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)"
or something like it