Paul,
> wheres the rule that says i need to put an alt tag on every image?
Actually, the alt attribute on <img> and <area> elements is one of the
few attributes that are actually *required* by the W3C HTML 4.01
recommendation [1]. If an image doesn't merit descriptive text (e.g., a
transparent gif, a bullet-point image, etc.), you should use an empty string
as the value of the alt attribute, i.e., alt="" (and not alt=" ", as some
might recommend).
James Aylard
1. http://www.w3.org/TR/html401/struct/objects.html#adef-alt