Le Happy Merchant is a an anti-"Jew" meme used widely among anti-Semites and the alt-right. It depicts a stereotypical Jew with yarmulke, oversized nose, greedy grin, and "conspiring" hands. It is common to see the image edited onto left-wing political posters or to see liberal candidates depicted as Happy Merchants. In short: it's a meme-friendly way to Jew-bait.
The image itself comes from a cartoon by the pseudonymous "A. Wyatt Mann" (say it out loud), a pseudonym for either White Aryan Resistance member Wyatt Kaldenberg (who eventually renounced white supremacy and denies having anything to do with it) or more likely director Nick Bougas (more or less a race-baiting hipster who was known for producing "anti-political-correctness" zines). It was one of a great many cartoons produced during the 80s and 90s by the same artist, many published by white supremacist Tom Metzger.