How does Google Index Images?

Well thats an interesting question, How Does Google Index Images?
Google Maybe the most comprehensive image search provider of the web. But some webmasters don't know how to get their images indexed by Google.

Googlebot as we all know ignores images. So, how the damm it has an image search?

If your site is "Search Engine Friendly" and is a bit old, then Google must index its images too.A bit old site is required because Google dosen't update the Image Index "frequently"
If you are an impatient Webmaster, like me, Google Webmasters have an option for Enhanced Image Search. If you choose to enable enhanced image search, Google will use tools such as Google Image Labeler to associate the images included in your site with labels that will improve indexing and search quality of those images

For those who don't know about Google Image Labeler.Google Image Labeler is a new feature of Google Image Search that allows you to label random images to help improve the quality of Google's image search results.

In this You'll be randomly paired with a partner who's online and using the feature. Over a 90-second period, you and your partner will be shown the same set of images and asked to provide as many labels as possible to describe each image you see. When your label matches your partner's label, you'll earn some points and move on to the next image until time runs out. After time expires, you can explore the images you've seen and the websites where those images were found. And we'll show you the points you've earned throughout the session.

it is not necessary that you do a bit of "labeling" to get your images indexed.Few more tips are that you


•Make sure the page topic corresponds to the search term

•Make an image of standard size{like 800 x 600 }

•Make the image in .jpg or .gif format.{Not necesarry, but recommended }

•Use the search term in the alt attribute, the title attribute and make sure that you have included the width and height declarations