It should be possible to use Ghostscript without installing it. You should first download and install Ghostscript on your own machine. If you want to use the x64 version of Magick.NET you should install the x64 version of Ghostscript. You need to install it because you need to copy the file gsdll64.dll or gsdll32.dll to your project/website. I have not tested this so you might have to copy the dll into your bin directory before it works. You could try to place it somewhere else first. Before you use Magick.NET in your website make sure you do the following call:
MagickNET.SetGhostscriptDirectory(@"c:\directory\where\you\put\the\dll\of\ghostscript");