"And no nukes, while you are at it"

I came back from a trip to Japan, South Korea, Hong Kong and Macau last week. A more detailed report is forthcoming, but one thing I noticed is the amount of interesting warnings, bans and advice. "Please see a doctor if you are sick", "Please drink water to avoid heat", no discharging missiles in the park and a lot of other stuff, etc.

The most mysterious, however, was this, in Tapgol park in Seoul. Why two pictures of people throwing trash? What do the head and the hand mean? Do they really mean "don't set fire to the buildings" in one of these? And what the hell is the fourth one from the left in the top row (a closeup)? My first guess was "don't measure chipmunks' temperature anally", as good an advice as any, but then my friends also came up with "don't abuse chipmunks in the butt with a sparkler", "don't give chipmunks pregnancy tests", and many other creative ideas. If any of my readers know any Korean, please shed some light on this mystery.