I'm trying to relocate a picture I've seen before on the web. It's an illustration — from some book, I assume — of the letters of the Hebrew alphabet each superimposed on a man's face supposedly to illustrate how each letter reflects the way it is pronounced. The pictures of the men's faces are rather post-mediaeval looking.

Has someone else seen these pictures online and if so, do you have a URL where I can find them again?

No, I have not found that. However, your question reminds me of Ophanim, which is Hebrew yoga involving twisting the body into positions that resemble Hebrew letters. The practitioners of this believe that they are acquiring the psychic energy of the particular letter they imitate. See http://www.angelfire.com/pe/ophanim

The source is up on Google Books now: Franciscus Mercurius (Baptista) van Helmont's book Alphabetum Naturæ:

http://books.google.ca/books?id=lvxSAAA ... CGEQ6AEwCA