The key feature of a Photobucket account we're talking about here is called "3rd Party Hosting." It allows you to embed images from Photobucket in another location on the Internet, e.g. in a forum post or on a website.
As Norvic Philatelics discovered, Photobucket changed its terms and conditions and removed the 3rd Party Hosting feature from the lower subscription tiers. If you want to continue using that feature then a Photobucket Plus 500 subscription is required. It costs $39.99 per month or $399 per year.
https://www.pcmag.com/news/354711/photobucket-breaks-image-links-across-the-internetThe worst part of this debacle, according to Ghacks.net, is the fact Photobucket users were apparently given no warning of the change. The subscription features simply changed, and images stopped loading without explanation
Even more, it seems to completely lock people out of their images, not just embeds (although that's what a friend who had some pics on there says, can't confirm if I understood correctly).