Google, Bing, Yahoo and all search engines are instructed not to index photos from a default installation of Joomla.With the advent of blended search results, why would you not want your images to be indexed and shown alongside your site in Search Engine Result Pages (SERPS)?
The problem comes from the default robots.txt file which looks like this:
First of all, delete the line Disallow: /images/
While you're here, it's a good idea to add your sitemap to the top of the file.
The robots.txt file is pure advice to search engines. You cannot rely on bad spiders adhering to its advice. For it to work, by nature, it has to be publicly readable and offers no protection against bots spidering where you don't want them to go. Of course, images can also be seen on pages by search engines, but it doesn't help when you tell them not to open their eyes!