The monster memory describes the black druid as wearing white robes and wielding a sickle, while his image has brown robes and carries some kind of skull staff.
This is just to say we should exercise some flexibility here - not every tile is going to perfectly match every monster description. We should also take into account some monsters have more than one description.
aerol -- that's true, but I think uniques like Keethrax should be held to a higher standard of consistency. There's a variety of orcs but there's only one Black Druid and the game should know what he looks like. (I assume the easiest fix is just to change the description to match the image but that's obviously up to Team ADOM.)
We can, um, change the monster description, too...
Personally I think *this* would be the better and more reasonable idea. Because unless the Monster Memory is extremely important to the monster, it is easier to change a couple words in text than to change a sprite.