We are continually testing the optimization of different elements on a page and in page code to better determine how the search engines weigh each item in their algorithms. Recently we conducted tests to determine Google and Yahoo’s preference for two elements of image tags – the Alt and the Title.

The Alt element is more familiar to many of us – it is used to describe an image to both the search engines and users who cannot view images. The image Title is used if an image is also a clickable link. The image Title describes where the image link is pointing to, since there is no anchor text for these types of links.

After testing the combinations of Alt and Title uses for image links, the preliminary results are in: Google prefers the use of the Alt and Title elements together, whereas Yahoo seems to consider the use of both elements for one image as spammy. Since Google’s algorithm places a lot of weight on linking, it makes sense that using the image Title to act as link anchor text would be viewed positively by Google. Yahoo’s algorithm may be designed to detect and penalize less-commonly used elements that appear to be used only for keyword placement.

Take-away? While the Title element of image tags adds value to the search engines and users who cannot view images, use it sparingly or not at all if visibility in Yahoo is a primary driver for traffic and conversions on your site. Perhaps a future Yahoo algorithm update will make adjustments to better reflect the value that the Title element of an image tag provides.