All major textures in the game were increased to 400%+ of their original pixels, sharpened, and had some detail added. Then new normal maps were generated to take advantage of the greater detail, which results in a significant improvement over the original graphics. This enjoys 0% compression files, which helps offset the fact that larger files requires more system resources.
The version that was shipped on gaming magazine discs had to have some of the material removed to fit. This is the missing files. If you do not have HiRes Lite then you do not need this file.