There are as many upsides to having your website's images found in image search at Google as there are downsides. The good part is that you will see an increase in traffic and exposure for your site and its images, but the downside is that you'll be paying for the extra bandwidth and run the risk of having images stolen by less scrupulous webmasters.
How to Get More Traffic From Google Image Search
This traffic-generating tactic is about as simple as it gets. Simply enable the Google Image Labeler. Google may use this tool to associate the images included in your site with labels that will improve indexing and search quality of those images. All you will need to do is sign into your Google Webmaster Tools account, select the URL for the site you want, click tools and then select "Enhanced Image Search." Once you have opted in to enhanced image search (you can opt out at any time by returning to this page and clearing the checkbox), you should start seeing your images indexed over time.
Tips on Getting More Traffic From Google Image Search
Most webmasters/SEOs/website owners have no idea how to get image traffic from Google. So the good thing is that if you do it right, you will get more
traffic. According to Google, the most important thing to have is
descriptive alt text in your image tags (but height and width apparently help with indexing as well) and a reflective title for the page containing the image. For example, once enhanced image search is checked with your Webmaster Central account, images in the code of your site might look like the following:
<img src="http://www.yoursite.com/images/Image-Search.gif" alt="Google Image Search Screenshot" width="496" height="211">
Here's how it looks within your Webmaster Central account: