Hmm, I have a few more thoughts to add.
The word "face"on its own can't be expected to convey anything more than eyes + mouth. An equal sign followed by a parenthesis is a face. That region of the body above the neck is not a "face." That is, when one human sees that region on another human, its brain doesn't just process "face", it processes all sorts of subtle details that authors fail to recreate in their writings, although it is difficult I'm sure.
And about my other imaginative capabilities--well, for one I can't hold a scene in my waking mind's eye (with no sensory input) much longer than a long GIF animation. I have to pause before I can continue and the clarity is gradually lost no matter what I do. The scenes are clear enough for me to describe where various items like furniture or people were situated and even sketch or map on paper, but it's all very noticeably hazier than seeing with my eyes and the field of view is reduced. With math I can roughly translate the notation into 2D graphs and some simple 3D shapes. I can't do anything like rotate a dodecahedron with distinctly colored sides in my mind and keep track of which colored sides are adjacent to which.
XiXiDu, are you well above average in mathematical ability? Your trait is correlated with it, strongly IIRC. At any rate, you should get yourself under an fMRI for science.
I used to have a lot of trouble seeing faces in both books and dreams, and I can only guess why I got better. To better visualize the faces of characters in books I consciously "cast" friends, actors, and mostly generic ethnic looks. And I also mentally design faces--I can choose brachycephaly or dolichocephaly, a concave or convex nose and anything in between, recessed eyes or bug eyes, jaw curvature and slope, etc. I can also classify anyone from Iran to Ireland with relative accuracy, and East Asians/Sub-Saharan Africans by broad geography. My guess is that my former interest in anthropology (e.g. looking at portraits with the nationality of the person captioned underneath)and real-life practice have trained my brain to make these distinctions, as well as the crowd I keep, but there's surely some heritable component to this ability.
A somewhat relevant quote: "In psychology one may or may not be a behaviorist, but in linguistics one has no choice." --W.V. Quine
I have tried to come up with a personal technical language that precisely describes my nonlinguistic thoughts and the result is a mess. I also have a constructed language (WIP) that's on hold while I learn Lojban. [Any Lojbanists around here?]
PS: Sorry about my low-quality posts. I'll try to meet LW standards in due time. Until then I'll read the blog and update my lingo.