Instead on trying to get people banned you might consider a softer approach and work with the staff and the posters to find suitable hosting solutions without robbing members of new content (which will be the case if the staff decides to go hog wild here).
Multiple warnings and suspensions can be a very effective method of achieving a given objective here. Many of these posters make a living (or at least additional income) by uploading content here and elsewhere. It only makes sense that many of these uploaders use a neutral imagehoster rather than trying to hotlink images from here elsewhere (which, even if it was feasable, would probably cause more harm than good).