That meme — referred to as 'Birthday Dog' on Know Your Meme but actually showing a dog named Riley – was just one of a number of photographs used to illustrate the inequality in American society during a KCNA television segment. Also shown in this segment (from around 2:40 in the video onward) is a bull terrier sitting by glasses of champagne, some dogs who appear to be having a tea party, and a dog known as Giant George, who is said to be the world’s tallest dog.
The dogs appear to have been chosen to illustrate the decadence of American society, where dogs are given birthday parties or allowed to grow huge while homeless people line the streets. The implicit contrast in the segment shows North Korea in a good light, with relatively little inequality due to the nation's planned economy. North Korean society often focuses on dogs, with dogs featured on stamps and the animals are sometimes eaten for their meat.
NK News, the North Korean-watching Web site that first brought the KCNA video to light, suggests that the use of online memes shows how limited are KCNA's research skills. That's certainly true, but like much of North Korea's anti-American propaganda, there's a kernel of truth to it: Perhaps the popularity of a photograph of a smiling dog eating a birthday cake really does show the nadir of American society in 2015.