This is how to edit the resolutions in Command & Conquer: Tiberan Sun.
First go to the directory you have the game installed, then modify the sun.ini file with a text editor.
What to Look For And What it Does!
You’ll need to put in the following lines in Sun.ini after the existing info if they are not already there.
[Video] ScreenWidth= ScreenHeight= StretchMovies=
The ScreenWidth= entry changes the screen width and you guessed it, ScreenHeight= changes the height. StretchMovies= is used for if you go to a higher resolution and want the movies to be stretched to the whole screen. Use Yes and No to set this option.
What to Change
First you should set the ScreenWidth=, put a valid screen width like:
ScreenWidth=640 ScreenWidth=800 ScreenWidth=960 ScreenWidth=1024 ScreenWidth=1152
Next set ScreenHeight= to a valid height like:
ScreenHeight=480 ScreenHeight=600 ScreenHeight=720 ScreenHeight=768 ScreenHeight=864
Now you can go higher but these have been tested with a 19 inch monitor and some weird things can happen as you go up higher. (I.E. the game not taking up the whole screen)
This was tested on the German and US versions of Tiberian Sun.