There are some errors in those maps.
For example, in the second image, the ground of the bottom of the bridge should continue for one more tile (but that would in turn, make the bridge asymmetrical; the real solution would be to add a central water tile in with an extra row of bridge tiles, then get rid of the two hanging bridge-rails, while leaving the bottom half of the map in it's place).
And in both images, the south wall is missing its roof tiles, and there are horizontal roof tiles going along the vertical side walls, when there should be a corner roof tile at each corner and then vertical tiles (that may be due to a lack of said tiles in the mapmaker, though).
Like Falaris said in the
other thread, it's basically common sense -- no background in arts or game design is needed.