You can always set environment variables without administrator privileges. We assume you mean you can't set Window registry entries. Grab the ImageMagick Windows source and build. The default is a non-installed build which does not require the Windows registry. You simply set the MAGICK_HOME environment variable. ImageMagick also looks in the same directory as the executable you are running so if you put all the configuration files in the same directory as the program you are running, ImageMagick should pick them up.