The rule on my website is to use URLs only. Imageshack's 1st URL link for forums seems to be the best. A full page image,with no links to click that doesn't hog your bandwidth.
PS for posting videos, use Tinypic. You get 100Mb filesize limits, for free, without signing up! I have posted lots of vids, and they are still up a year later. The only thing I dislike about Tinypic is that they changed their player. It used to have a nice, mature looking brushed steel look, but now it's really childish and multicolored. Maybe most of their users are 11 year old girls...