The Alt attribute gives you an opportunity to place another reference of targeted keywords on your page.  Use these attributes to increase keyword density, but avoid exceeing >6% keyword density on the page.

The Alt Attribute

The intended purpose behind the Alt attribute is that if an image does not laod, the  Alt attribute would be displayed in it's place. Additionlally, Alternative Text Tags serve Visually impaired web surfers as the text could be read aloud by their web readers.

The Alt attribute can help you increase keyword density and therfore page rank in the search engines, but it can also hurt your site if you abuse it. You should not exceed around 6% overal keyword dnsity on each web page.

Keeping alt text both useful and simple is the best way to maximize the benefits without running the risk of getting a keyword stuffing penalty. While many simply describe what is in the picture, this may not always be the most effective use of this SEO opportunity.

The Title Attribute

The title attribute is used exactly like the alt attribute in that it is used to further identify an element. Some title attributes are shown on the screen to site visitors and others are not - this depends on the HTML tag and the browser being used to view the page.

The most common uses for the Title Tag are on Anchored Text Links and Images.  The Title Tag will appear when you hover the mouse over these elements as a "tool tip" to greater define for the useer what the element is.