In Korean culture, the pig is a very positive animal. There's even a superstition that dreaming of a pig means you'll win the lottery. That's why it's also used to wish someone good luck.

It's one of the twelve animals of the Eastern zodiac, representing people born in the Year of the Pig. While it can be a symbol of "greed" in the West, in Korea it's more often used for humorous resolutions like "diet starts tomorrow" or to affectionately tease a friend who eats a lot.