Here's a quick tutorial on how to use the Command Line:
The Command line is used to change what the program does during start-up.
To set your shortcut to use a command every time you launch the game, you can right-click on the Guild Wars shortcut and choose "properties." In the properties window, look for the text box labelled "target" with the path to where Guild Wars is installed on your hard drive (e.g. "C:\Program Files\Guild Wars\gw.exe"). Add the necessary parameters after the target path.
-image
This will download ALL the files from the server... this means you won't have to download on the loading screens anymore, quick and clean map-change...
After having downloaded all files the program will exit automatically, so make sure you to take out the command of the command line or you wont be able to start your game anymore...
-password xxxx (xxxx is your password)
This will log you in automatically without you having to enter your password anymore, but it's not advised to do this if you're sharing your computer with anyone else... ^^
There are also some more commands, but these are the most important ones (at least in my opinion)
Hope this helps you,
Kazuki
Subject: Command Line 
Mon Jan 14, 2008 9:56 am
