It is possible to install GD on windows, I used the ppm package at http://theoryx5.uwinnipeg.ca/ppms/. In my experience, relying on preinstalled GD in shared hosting can be difficult. I once had an isp that supported GIFs in the GD library but used an outdated GD.pm meaning that any GIF operations failed. So it is best to avoid GIFs in GD altogether if you want portability.
in reply to Re^3: Image generation
in thread Image generation