Generals / ZH was made at at time when computer screen resolutions were lower, up to 1024 x 768.

Now that they are much higher, I want to modify the in-game dialogue box to enable the player to select higher screen resolutions. Anybody know how to do that?

It is of course possible to manually set the resolution to whatever your screen is by manually editing

<User>\Documents\Command and Conquer Zero Hour Data\options.ini

And I think there are also command line parameters to start it in a certain resolution so for example, you can modify your shortcut file to use:

"C:\Program Files (x86)\EA Games\CnC Generals\ZeroHour\generals.exe" -quickstart -noshellmap -nointro -xres 1920 -yres 1080

but I want to make it possible to set a higher screen res in the in-game options dialog.