Now that I’ve had a chance to sleep on this, I can see a potential problem with forcing people to use url’s linked to pictures off-site. What can happen is people deliberately leave a link to what they describe is a particular legitimate picture when in reality it’s to a very, very nasty site, designed to do nasty things to your computer, or even to a website with highly illegal content. This can, and does, happen elsewhere. All we need is a pissed off person deciding to leave, but not before leaving a parting gift. Another problem is that they could be providing a link to a legitimate website with a legitimate picture, but that website later disappears and is replaced by one of those nasty sites previously described. That’s a problem that’s occurred here at least once.
Oh, and I’m assuming this is what people are talking about, linking to pictures that are hosted off-site?