Images shown in regular search result pages offer great marketing opportunities. Most search queries in Google image search aren’t very competitive. So images that are properly optimized can rank well in both Google image searches, as well as natural searches where they display four or five images on the first page.
To rank well for an image on a given keyword, it is important that the image URL/image name, as well as the alt attribute, includes the keyword. Equally important is to make sure that your image on your website page has keyword rich textual content around it.
With the increase in popularity of image sites like Pinterest and Flickr, as well as the sharing of pics on Facebook, it is important that your website images get found in search results. They become another opportunity for hooking and directing traffic to your website. Optimizing an image also slightly helps a web page to rank well for a given keyword.
Bottomline, this is an area where your competition is still fairly inactive. Taking advantage of optimizing your images will give you a “one-up” on your competition.