Of course no one will seriously suggest a gif prohibition (I hope), but regarding fake news specifically, regulation such as the FCC Fairness doctrine could possibly work.

The point is not to eliminate undesired behavior entirely, but to make it less available and less desirable compared to alternatives. For example, smoking cigarettes is being largely successfully solved by education, promotion of general health, gross packaging, putting cigarette cases out-of-sight in supermarkets, and taxes, not outright prohibition.

I don't think that just because the content is digital you can't do anything about it without introducing worse problems for freedom of speech and such. Tons of industries are successfully regulated, this one is not special enough to be unsolvable.