I joined this forum few days back only so thought to contribute something which has proven quite successful for me:
Have you recently tried seeing How Google is showing results in some search pages? It does show image results too and to everyone's surprise people do click on these images and some even buy something. My personal experience is conversion is less , but then what if you can get some sales its not bad.
Now how to get ranked for Google Images:
1. Use alt
attributes for image tags properly. Specify the keywords. Please don't spam these attributes with lot of words, just mention what the image is all about.
2. If possible just above the image make a heading, and use some keywords related to image in that heading.
3. Image size should be decent enough approx greater than say 200X250 pixels (its just my guess after observing how my images have been listed)
4.If you use GOOGLE webmaster tools, there is a setting in it to enable IMAGE LABELING for your website, enable that.
Leave it to Google to do the MAGIC. Not every image of your website will rank well. But say you have 100 product images and if you are able to get good ranking for 10 products you will get some traffic daily to your website.
For me now a days I am getting 3% of traffic form images. And in last one year I got 1% of sales from traffic through Google Image Search.
For those who would like to spend bit more time in understanding it better here is video from GOOGLE itself:
I hope you liked my first post to share this information with you and I will contribute with much more in future
Obviously if you all think its worth it. So give me