Identifies the different modes of palette handling.

Values:

IG_DSPL_PALETTE_HIGH	Use the palette in the high priority mode. This means that the operating system palette manager will try to best map colors of DevicePalette to the system palette.
IG_DSPL_PALETTE_LOW	Use the palette in the low priority mode. In this mode the palette manager will try to best preserve current view of the destination while drawing the new image on it.
IG_DSPL_PALETTE_DISABLE	Not to implement DevicePalette in the destination device while drawing the image.