Classically, I think the text data was considered the most important to keep decentralized. For politically controversial posts, the images are mostly window-dressing to the text content. And of course, all the financial data is decentralized.

Nonetheless, the image server data is distributed across multiple servers now, and the plan is to truly decentralize this data as well. You can search thru my previous posts to find more details about this plan.

In a similar way, I expect the same thing to happen to the video data with time, but the video servers are maintained by other groups right now (e.g. 3speak) so they will likely move on their own timelines.