Update build instructions

docs/BUILDING.md

@@ -1,13 +1,15 @@
 # Running from source
 
-1. Get [python](http://python.org/downloads)
-1. Get the [Door Randomizer Unstable source code](https://github.com/Aerinon/ALttPDoorRandomizer/archive/DoorDevUnstable.zip)
-1. Install Platform-specific dependencies
-1. Run `DoorRandomizer.py` for command-line script
-1. Run `Gui.py` for user interface
+|Instruction|Image|
+|-----------|-----|
+|Get [python](http://python.org/downloads)|[Get python](images/python.png)
+|Get the [Door Randomizer Unstable source code](https://github.com/Aerinon/ALttPDoorRandomizer/archive/DoorDevUnstable.zip)|[Get source code](images/sourcecode.png)
+|Install Platform-specific dependencies (see below)|[Command line](images/cmd.png)
+|Run `DoorRandomizer.py` for command-line script|[DungeonRandomizer.py](images/py-dungeonrandomizer.png)
+|Run `Gui.py` for user interface|[Gui.py](images/py-gui.png)
 
 ## Platform-specific dependencies
 
-### Windows
-
-* Run `resources/ci/common/local_install.py`
+|Platform|Command line|Image|
+| :----: |------------|-----|
+|Windows |`resources/ci/common/local_install.py`|[Windows](images/cli-windows.png)