Alt tag is the alternative tag, i.e. for those who can't see pictures, it gives a description of the picture
alt tag is an attribute that is used as an title to the image......it is the best way to optimize the image .it in turns the gives the page rank to the website.....
At SEO point of view alt tag is very important because Google crawler also crawl alt tag and give its important, so try to promote you keyword in the alt tag.
Alt Tag used for Image optimization . In Which , We provide the information to search Engine Spiders about image .
Actually Seach engine spider cant able to crawl and indexed actual image .so "alt" attribute basically provide information to the crawler about the image and its type.it is also similar to "title" attribute .
Alt tag is attribte, it's an alternative text which is set on an image, Seo point of view crawler not reads the image so we put an ALT tag on image, so crawler reads the text. After putting the cursor for a second on any image we can see the alt tag value.
keep u r points with you not even a single easy answer expect one why don't some take screen shot and explain him
alt tag is a title for the images. You can use targeted keywords for the images as a alt tag. It will help you to get ranking for that targeted keywords...