Anyone has some good suggestions for OS & self-hosted meme generators?

There is a reason why Facebook bought giffy, as it is an ideal tool to track users and chat-groups (link to meme gets posted and the clients auto-download it, of course server side caching helps in that regard).

I think this kind of tools would be a good addition to the self-hosted repository of things, especially if easy to use and integrated in chat clients.

The above link is an example I found quickly, but other suggestions are welcome.