A Japanese photographer namedposted them to his Website. He also trained Oolong to balance a variety of objects on the rabbit's head. The photos really are charming; you can see Oolong playing outside, sleeping, and yes, balancing objects on his head. Oolong had regular excursions outdoors, and even liked to play in the snow.
Links to the Web site and pictures of Oolong began to circulate, especially after Syberpunk, a geeky culture site about Japanese culture, wrote about Oolong. Two pictures in particular became wildly popular. A picture of Oolong with a waffle on his head, and a picture of Oolong with a Japanese pancake, a dorayaki on his head. The pancake picture took off as a macro image, when some unknown person posted a macro image of Oolong with the caption "I do not know what you are talking about so here's a picture of a rabbit with a pancake on its head." An image of Oolong, with or without a macro, became a fairly common way to indicate that a previous poster was not making sense in a blog thread or in an online forum. It's dismissive, much the way the Internet acronym "tl;dr" and varients of Too Long; Didn't Read" are dismissive.