Search Engine Optimization - Image Alt tag

The ALT attribute of the IMG is intended to be used as alternative text for situations where the IMG is not being displayed.

"Several non-textual elements (IMG, AREA, APPLET, and INPUT) require authors to specify alternate text to serve as content when the element cannot be rendered normally."

Avoid putting line breaks in your source HTML within your ALT texts, as some browsers display badly. If necessary, start on a fresh source line before the ALT= attribute, and end the source line after the closing quotation mark, but don't break the source line anywhere between.

Remember to always provide WIDTH and HEIGHT attributes for each <img> tag. This enables the browser to display the rest of the page correctly before the images have been loaded. Without these attributes, the browser might have to wait until all the images have loaded to display anything, or it might have to refold the document several times as each image is loaded.

Search Engines and ALT tag.

One simple technique can improve your search engine rank, make site navigation easier, and increase the accessibility of your site to disabled visitors. Many sites don't use it! Boost your site's profile with human visitors and search engine spiders with the ALT tag.

The image ALT text description should be complete sentences, rather then a list of keywords or obscure phrase like "or company logo big". Remember that all visitors are likely to see or hear some version of the ALT text so be sure that's meaningful.