Matt (Omega93) is a pixel artist who likes to draw on Miiverse, but doesn't consider himself to be perfect at what he does. He tries to experiment with different methods with his drawings. So far he has come up with at least 3: 3D Pixelization, Pixel Fragmentation, and Giant Pixel Drawings. He was only going to do pixel drawings as a one-time thing, but after receiving some feedback, he decided to continue and have fun with it. He doesn't seem to participate in many events that go on in Miiverse though.
He is the founder of a group called PixelPaintClub in DeviantArt. In that group, only drawings made from Pixel Paint are accepted. There are monthly contests hosted by him and his Co-Founders; right now they are currently working on some ideas for prizes. There will also be Pixel Paint Challenges issued only by him; set with restrictions on how you draw. You can find the club here
After two months he had finished his profile picture, it was taken down due to reasons unknown. Two work in progress posts were also taken down as well. He then contacted Nintendo via email. A few days later, one of the employees answered; even he was uncertain as to why it was taken down. Once he got back from talking to his superiors, he mentioned that the reason why they took it down is because the drawing of himself looked so realistic that they thought he somehow copy and pasted it. When they looked it over again, they realized that it was indeed drawn, so they brought back his post; along with his WIPs.