It doesn’t really work the other direction. Mastodon users can post and comment on Lemmy communities by @ ing the community. There isn’t a way for Lemmy users to browse hashtags or users from Mastodon. Even if you click on the user profile for a mastodon user from Lemmy, it’ll only show you the stuff they’ve posted and commented on Lemmy instances, not the full activity of the account.
https://perchance.org/ai-character-generator
It says character generator, but you can totally use it for other stuff. It’s just stablediffusion. I’ve used it to generate illustrations of locations to show to my Pathfinder players.