Creating a good search system is very complex and difficult to do. It took Google years to get to the point where we know it today.
Actually....... Google was very good at the beginning, so the search part they had covered. The point where they are today is based on earning money, and no longer on providing the best search results.
Ninjastic Search works fine for searching, but only if you type the exact right keywords. That's what Google excelled at: showing me what I want to see, even if I don't know exactly what it is. If I place my right hand incorrectly and type "botcpom", Google knows I mean "bitcoin". But that would go far beyond the scope of a forum search engine.
To get back on-topic: a fully decentralized forum would also mean a fully decentralized search. That's great for privacy, nobody else will know what you're looking for.
The idea is simple, someone who may download hosted images from imgur and other image hosts and then upload those images to TalkIMG and may link those images to the posts/threads of the backup torrent.
From imgur alone I downloaded
801,550 pictures and 146 GB. But there's a bigger problem: a decentralized forum should be immutable. If
someone can edit the image links in all posts, you can't be sure what else they've edited.