I think the ones that baffle me most are the ones that are in low def, about an eighth of an inch by a sixtieth, and show a vague outline of a fully dressed woman somewhere in the distant background. And... there's a fair few of those.
Actually, I think profiles with reasonable quality, or good quality photos are actually in the minority.
Its a mystery. I can easily understand absence of a face shot on some profiles, but really can't see why some good quality shots showing overall figure aren't the norm.