Is a rectangular hole in the wall with no pictured door actually a door?
By the rules reference I'm inclined to answer yes, but is that really correct? Why then depict doors on some openings and not others????
Are there doors when none are painted (that is in doorways without an actual door)?
The artwork on the tile is really "fluff", it's really just decoration.
What matters is if there is a WALL (solid brown lines) or some sort of BORDER (solid white lines, solid yellow lines) or IMPASSABLE BORDERS (dashed white or yellow lines).
If there is a gap (with no dashed/solid white/yellow lines) in the thick solid brown wall, then it's a door. It doesn't matter if the artwork shows a door or not.
It might help if you gave an example of a tile which may or may not contain a door.