Alt Attribute Importance In SEO
A lot of discussion comes from the area of the importance of alt attributes on images and their effect on search engine optimization.
If you don't know what an alt attribute is, Is the attribute that makes text appear when you mouseover an image, It is not a tooltip and it is not a tag.
Alt attributes were created initially for text based browsers, Like lynx, Which can not display images. The alt (or alternate) text was to describe what it is an image of, and should still be used only for that.
Alt attributes are put into code like this:
<img src="http://www.domain.com/images/logo.gif" alt="Some Text Here">
Google does include the alt text as body text,So in theory people could find your page by searching for what you have in an alt attribute. But it is believed that not much weight is given to this text, So really it's a good idea to use it for what it is intended, Too describe the image, and keep your text in the body of the page in areas that are readable to your users.