Dyvers is talking about his favorite D&D art this month and he starts out by asking “Do you remember the first great piece of art you saw?” I think I’ll translate that into what art pieces first shaped my perception of D&D.
My answer is basically all of the art found in the Moldvay Basic Set (Acaeum, specifically the eighth printing). That was my first and only exposure for several years. It was followed up by The Expert Set and then AD&D pretty quickly. While there are a lot of iconic images to be found the box cover it self pretty much says it all to me: dungeon, dragon, magic-user, fighter, and treasure.
The race and alignment illustrations are probably the next most influential. I didn’t read The Hobbit until a few years later so Halflings looked like adventurers, not well fed Hobbits. And Neutral meant ambivalence, not balance. That nonsense didn’t start showing up until the Druids came on to the scene.