If you don’t want images included on your page to appear in Google, you can use the noimageindex value in the head portion of your HTML page, as shown below (note this value is not new – quite the opposite, it’s been around for years – though it’s one of the more obscure ones):
<meta name="robots" content="noimageindex">
However, if other sites directly link to your images, then Google may still index them, as they explain on their help entry on the subject.
A more stable way than above to keep Google and others away from your images is to put all images into a special folder on your server, like "/images/" Then, you can add a robots.txt file to your root and put the following text in it:
User-agent: * Disallow: /images/
Conforming user agents will now not crawl that folder, and so they won’t be able to generate thumbnails from your images to put on their server. In theory they would still be able to link to your file – e.g. if they found the link to it on another website – but in practice, they currently won’t.
Then again, the question is why you’d want to keep spiders from grabbing your pics in the first place. There may be some small bandwidth costs when crawlers download your files, but image search engines can send a whole lot of traffic to your site. You may even be able to create a site which gets the majority of search referrers just from image searches, as opposed to web page searches.