Jawas and Sand People

Within the first half hour of the first Star Wars movie, we're introduced to the Jawas and Sand People. These indigenous folks from Tatooine are essentially the first Aliens to ever be introduced in the entire pantheon of Star Wars. Their respective cultures and traits have been fleshed out over the years, as with so many other alien races.
So why is it that nobody knows what either of them actually look like? You'd think after over three decades somebody would have come along and canonized exactly what they look like beneath their hoods and masks. But obviously they haven't. And it makes me sad.