setting "pre-read images" to false

[xeniorn]

There doesn't seem to be a way to prevent warpcraft from pre-reading images in memory. Default is set to "true" and neither of the following makes it become false:

1. --prereadparticles False
2. --prereadparticles false
3. --prereadparticles 0
4. --prereadparticles -1
5. --prereadparticles 1
6. --prereadparticles no
7. --prereadparticles F
8. --prereadparticles F

is it hardcoded or is there some other syntax that would need to be used?