Poster graphic design by Patricia Tyler, NASA/GSFC:
The caricature in the center was based on my 2001 staff photo (below), and was created by Steve Holt, longtime X-Ray astrophysicist at GSFC, former director of Code 660 and later Code 600 at GSFC.
This was the (35mm film) staff photo I took of Peter circa 1991:
This profile of Peter was from June 2001, taken at the Code 660 LHEA Peer Award picnic. (So it's a decade after the one above, although it looks like the same shirt!)