2008/6/16 Lane, Ryan Ryan.Lane@ocean.navo.navy.mil:
It's better to display it as alt text, so that the irrelevant information is hidden if the browser does in fact support images (which will practically always be the case).
Wouldn't this cause confusion for people using screen readers?
Yes, I think it would. Alt text isn't just used if the image hasn't loaded, it's used whenever the image isn't available to the user, which includes screen readers.