Since the launch of HTML 3.0 we have been seeing this IMG tag attribute called ALT. Now with XHTML, it is a manditory field. However bad information is constantly being put into it.
The alt field is there for ADA and search engines. Having an image of your logo, and company name, but the attribute only says “logo” is a waste of time. If your company name is that logo, then you need to use alt=”My Company, LLC”, or what ever your company name is.
I have a friend that sends out newsletters that are 100% images. his alts read “1×1”, “1×2”, etc. Now that is a waste of good marketing info. The alt needs to be a solid description of what the picture is describing.
The image is about a radio broadcast for a band. It has all of the details of the band, the radio station, and the timeslots. So the alt should read: alt=”GreatBandOFire live on XM Radio, Friday nights, 7pm. Join us.” Now that is a useful alt.
This is what finally brought me into looking at the mis-use of alts. A company that shal remain nameless, 4 years ago decided to go to xhtml. Yes, they were an early adopter for a lot of new stuff. But they also wanted their site to be visually savy. So they made all of the static content out of bitmaps. Including some animated gifs.
Not bad I thought, until I ran a text parser, common tool for search engines, and it could not find their company name, or contact information on the site.
Well, a simple change of adding the proper alts solved that.
So, should you put useful information into every alt? No. Some images have no valid alternate text. for those, just use and empty alt attribute: alt=””.
I hope this helps you in puting out browser and search engine friendlier websites.
Please note, this applies for HTML emails and RSS feeds too.