I think I have some expertise in this area...
The reason I tell builders not to use pictures is to prevent problems like 1x2 walkways or 5-wide houses or Arceus knows what else. I know for a fact that some trees in Johto are 3 steps tall, while others are 2 tall, depending on where the tree is found in the game. If you aren't doing anything with walking distance, use all the pictures you want. If you're just designing a building, AdvanceMap can barely help you. Cuz lets face it, that house over there is not 4 blocks tall. It's probably going to look better 6-7 blocks tall. As long as the person who outlined the walking width and depth of the area was using a proper scale, there is no more help a mapping program can give. It's when builders blur the lines between scaling and designing that I start to get irked.