This tool imports elevation data from an 8-bit grayscale raw bitmap image, and exports it to an uncompressed C&C Generals map file. It is recommended to use Adobe Photoshop in order to export the image to a .RAW image file.
You can see the tool being used in this World Builder tutorial.
Tools
Elevator

FinalBIG

A tool for creating and extracting files from .BIG files.
WAK Edit v2.0

This utility allows you to create ocean waves for C&C Generals and Zero Hour maps. It is supplemental to the World Builder tool, which, by default, does not support WAK files or the creation of waves.
XCC Mixer

This tool is a mix manager. It contains viewers for CPS, DDS, PCX, SHP, TXT and more. You can extract everything from the game's .BIG files. This tool can also be used to modify hotkeys.