O.J. Simpson New Mug Shot -- 50 Shades of Gray

O.J. Simpson was back in a Las Vegas court today in the hopes of getting a new trial in his armed robbery case -- and he marked the occasion by snapping a brand new gray-haired, fuller-faced mug shot.

O.J. -- who was transferred to a new jail facility while he's in court -- wants a new trial on grounds his old lawyer Yale Galanter provided inadequate representation, and was even a witness to his criminal plan in September 2007 ... when O.J. and 5 goons robbed a couple of sports memorabilia collectors at gunpoint in a Vegas hotel.

O.J. was convicted the next year of kidnapping, armed robbery, and ten other charges.

He's been serving 9-33 years at the Lovelock Correctional Center ... where, apparently, the food is delicious. And plentiful.