The alt attribute is a method of providing a descriptive text alternative for images. Reasons for using the alt attribute:
To display a text equivalent for an image in browsers where images have been turned off
Reasons:
[blockquote]To speed up page load time for users on slow dial-up connections.
To avoid viruses that can be spread through image files, where the user does not have adequate virus protection.
To save bandwidth when users are concerned about using up download limits.
To save download amounts if using a pay per download scheme (e.g. when connecting to internet via a mobile phone)
To aid browsing when using a handheld device e.g. PDA, mobile phone, electronic books, Blackberries.[/blockquote]
Accessibility purposes for users with disabilities:
[blockquote]For those who use assistive technologies such as screen readers which convert text-to-speech, sound icons, or a braille output
For those with color blindness which precludes them from distinguishing detail in images.
For those using audio-based browser technologies[/blockquote]
Search engine optimization:
[blockquote]Most search engines interpret the meaning of objects by analyzing their alt attribute. They cannot see images!
Use keywords in alt text to help with indexing and pagerank.[/blockquote]
For instructions on how to add the alt attribute to images please continue reading here: The Alt Attribute
