Image posts do not exist and we usually prefer medium to long text and videos that are dense with content. It’s not entirely formal though, and there are avenues for conversation and personal expression. The announcing post: https://blog.tildes.net/announcing-tildes
Extended docs and the philosophy of Tildes: https://docs.tildes.net/philosophy
Tildes' content is open for anyone to see: https://tildes.net/
We have a subreddit: /r/tildes with a permanent thread for invites and there are invites for everyone.