am I missing something here?

When I try to validate code as xhtml1.0 strict and within the img tag i
have a border attribute. The code does not validate.

I was looking at the source of the www.w3.org home page and I noticed that
the img tags for the xhtml1.0 strict logos at the bottom all include the
border attribute. Yet the page still validates. Whats going on here?

Thanks