Do content providers have to pay certain royalties with h.264? I thought the players were free of royalties and the license was paid for encoded content. And then with h.265 I thought I heard that there were two different license pools with different licensing strategies.

I'm not sure that meme generators have royalties very high on their list of concerns, the big hosts that host a lot of them might have some concerns about it though.

At this point, a newer webP based off the newer VP10 might be the only realistic PNG, GIF, and JPEG replacement but it doesn't exist yet.