Nothing, absolutely nothing is free, nor should it be expected to be. Servers cost money, disk space costs money, traffic costs money, producing software costs money. I don't use services like photobucket because I believe they are deceptive, just like facebook, and hook people into giving them something under the pretext of free. Photobucket fooled a lot of people, but they have to eat as well.
If this site wants to ban one file sharing site, they need to ban them all and only allow images that are hosted here. That is the only thing that will ensure the integrity of the threads.