How much detail should alt tags have?

[Workerbee]

I am going to be adding graphics to my site that show the locations of various towns in my state (in the US). The graphics are small, with no detail (just an outline of the state with a star where the town is), so the information provided is pretty general (Town X is located in the North Central part of the state).

My question is, how detailed should the alt tags be? Is it enough to have a generic tag like "State Outline," or should it say "State Outline showing that Town X is located in the North Central part of the State?"

I'd appreciate any input you might have on this subject.

Thanks,
wb

[ukgimp]

If you want to use them to increase rank you may be out of luck:

[webmasterworld.com...]

Keep them simple, but detailed enough so that a user who does not have images inabled can still navigate and understand your site. Turn the images off and get a non familiar person to try and navigate the site.

<added>By the way I forgot, welcome to WebmasterWorld</added>

[BlobFisk]

Welcome to WebmasterWorld, WorkerBee! Check out Marcia's excellent WebmasterWorld Welcome and Guide to the Basics [webmasterworld.com].

There is also a longdesc [w3.org] attribute that allows you to link to a text/html file that contains a longer (than the ALT) description of the image. It's main use is in accessibility, and the browser supplies a method to access the long description information. Support for this isn't mainstream yet (I think), but future browsers should implement this fully. If is a W3C standard.

[Workerbee]

Thanks for the info, and for the welcome! It definitely makes sense to me that the text of the alt tag should reflect the meaning of the image. I had heard about longdesc but have never tried using it - thanks for the link.