I'm finding a lot of older, more popular threads containing "How I did X" information have their pictures disappearing, either because the image host removed them, limited access to them (I'm looking at you, Photobucket), or stopped existing altogether. Similarly, some howtos here are nothing more than links to other long-disappeared sites. This makes it incredibly difficult and frustrating to find information.

Can we put a sitewide notification up, maybe a banner at the top of each forum, or perhaps mass email, and get people to start hosting their images either here on TGO or a major, popular image host that's like to be around forever, such as Imgur?

 

What you describe is not a ThirdGen only issue but is part of the Internet. I don't know that I'd guarantee that any of those sites would be "forever" or that they wouldn't change their usage polices.