Because it sure looks like it does.  For my sites we disallow the images directory and the previews are all missing images which makes the site look wonky.  Is this the case and is there a way to allow just the preview bot to access images using robots.txt?EDIT: It looks like the previews are generated both by the normal Google Bot and by an on the fly bot Google Web Preview as mentioned (briefly) on the Webmaster Central Blog.  By using a site: search and my monitoring software I could see when the bot hit my site and when this happened the images showed up just fine in the preview.  So my guess is that the normal crawler ignores the images per robots.txt, but the preview crawler gets the images anyway.  This implementation seems kind of crumby because my options seem to be:allow google bot to crawl my images (which I don't want to do)use the nosnippet tag which blocks the preview, but ALSO snippets (which I don't want to do)Let the wonky previews appear which may adversely affect click throughs
Does Google Preview obey Robots.txt?
google;robots.txt
I think John Mueller had it right in the comments.  If it's just a matter of not having the images indexed, you could allow crawling but serve the images with an x-robots-tag HTTP header with noindexI didn't know that you could allow Google to crawl content w/o indexing it.  I put his technique in place and am just waiting to get crawled to see if it worked.I'll accept this as the answer in a few days unless John wants to add his comments to the answer section so he can earn the rep.