How To Write an Alt Tag For Website Logo?

Should each webpage have a different alt tag

[contentmaster]

My website logo (on all webpages) links to the Home page. The logo on the Home page has a descriptive Alt tag that basically defines what the website is about. However, I am not sure whether it is good practice to include an Alt tag for the website logo on each of the webpages of the website? If yes, then what is the ideal way to write the alt tag - should it describe the website or should it be tailored to describe the content of each individual webpage?

[Quadrille]

ALT attributes describe the image they are attached to - NOT the page OR the site as a whole.

So the same image on different pages should carry the same ALT text; along the lines of 'company name - link to home page', 'company logo' or whatever, in the case you describe.

While I doubt that varying the ALT text would get you a ban (unless an obsessive rival added it to a list of transgressions), it is an abuse of the purpose of the ALT attribute, and would certainly cause confusion for visually challenged visitors, as well as image searchers.

[contentmaster]

The website in question is doing okay in terms of ranking and there are quite a few pages. Do you suggest changing the Alt tags throughout the website to make it more descriptive of the logo ie, : Company Name and not the page? I would not like to have any attribute on the website that puts it in any sort of risk.

[Quadrille]

I'd certainly be sure to use ALT appropriately for the future, and clean up where you can with 'find and replace'.

But unless you've seriously abused ALT, I'd not worry too much about what you've already done, except as part of general site tidying.

The exception would be if you have rivals who are likely to to be looking for trouble (rare, in most niches!).

[contentmaster]

And what about sites that don't use the ALT at all for their logos? Is it okay not to have any alt tag at all - especially for the site logo?

[Quadrille]

From an accessibility POV, you should use the ALT attribute, but my guess would be that the logo ALT is less important than some, as its place on the page might imply that it was a logo rather than something else.

It's a good habit to get into, and there's little doubt that there's some SEO value, too.

[edited by: Quadrille at 3:18 pm (utc) on Sep. 11, 2008]