Seattle-based Imagekind has launched a new greeting card product, which allows artists to sell their art as a set of greeting cards. ImageKind said its new product allows artists to sell greeting cards in single, 12-pack, or 24-packs. Imagekind operates an online marketplace for frame art, art prints, and more, and is venture backed by Holtzbrinck Ventures, Crosslink Capital, Curious Office, and others.