Requirements:
- Install Python2.7
- https://sandbox.idre.ucla.edu/sandbox/tutorials/installing-gdal-for-windows
- Install GDAL-core Atlas/gdal-201-1600-core.msi
- Install GDAL-Python Atlas/GDAL-2.1.3.win32-py2.7.msi
- Add Program Files/GDAL to your System path Now, when running the GDAL command line, you have access to gdal2tiles.py.