/* 
 * All of the samples I’ve seen are 8 bits deep, so we assume
 * that. Yeah, yeah, that’s nasty and evil, and I’m terribly
 * ashamed of it, but I’m not going to bother with bit
 * fiddling until I see an image that needs it. I once had
 * a 16-bit Galileo image of Venus, but it got lost (sigh).
 */