Google has added 150 million images to its searchable database.

Currently still a "beta" version of the search software, Google looks at the text on the web page around the image, and accompanying caption, among other elements to determine an images content.

"Google image search looks at dozens of factors to determine the image subject matter to ensure relevant images are returned to the user, leveraging similar ranking technology used for Google's HTML and PDF search results," Google spokesperson David Krane told SearchEngineWatch recently.

Results are displayed as thumbnail images - up to 20 per page. Each thumbnail features the size (in bytes and pixels), filetype and URL of the image. Clicking on a thumbnail brings a larger view of the image and a view of the picture in context on the web page where it resides in a lower frame. The images can also be viewed alone.

The searches can be very effective. A search for "Carole Levitt" resulted in two results, one of which was a photo of the Internet For Lawyers President. In its article titled "Thinking in Pictures" (scroll down the page to view), The Standard presents a side-by-side comparison of the Google, Altavista and Ditto.com image search engines.

The Google image FAQ page claims that "Google also uses sophisticated algorithms to remove duplicates," but a search for images of Hillary Clinton yielded a number of duplicate images (granted they were located at different sources on the web).

Users can locate the search at http://www.google.com/advanced_search and http://images.google.com.