Whenever we think of search engine optimization we generally think about how elements like content, links, title, and so forth affect page rankings. One of the elements that doesn’t get a lot of attention is images. For page-level searches images probably do not add very much weight. We know to add alt tags, but that is more for accessibility than SEO. There have been a lot of questions as to whether Google could pull text out of images — they are one of the leaders in OCR after all and use scanning technology extensively in their Google Books project — but all tests to date indicate that they are not incorporating text elements contained in images into their algorithm.
One piece of information in photos that does appear to be used is the Exif meta data associated with the image file. This information normally appears in photos taken with digital cameras and can tell things like date, resolution, and technical aspects of the camera and software used to produce the photo. Tools like Adobe Bridge can be used to add further meta information such as the subject of the photo, people or places shown, and an open description where you can put whatever keywords you want. We do know that Google can access this information, so we should be using it and making sure to give our pages every bit of optimization we can.
I asked our graphics specialist about whether Photoshop had the ability to put this meta information into images produced there, and he indicated that it does not. For those, then, we would need to make use of tools like Adobe Bridge and put in important contextual information. This would be especially important for things like logos and page feature photos.
Beyond what this can do for our page rankings, let’s also think a bit wider. Google also offers a specialized image search. You don’t even have to explicitly go to that function, most returns that have closely related images have prominent “Images For” link right there on the search returns page. Looking at the images returned for a search on “Texas A&M University” shows almost none of them from our sources. Many people look at images and then click through to the page containing one they are interested in, so optimizing images as well as pages, then, could give a second avenue to our content.