He's probably just paying homage to an album that changed his life, not that serious. People get tats of more dumber sh*t.
i don't got a problem wit what another man decides to get for a tat, but if it were me and i wanted to pay homage, i would probably just get "the chronic" as a tat somewhere else instead of the cd cover wit Dre's face especially on the side of my abdomen. I wouldn't want another dude's face tatted on me no matter how good of friends we are or how he has helped me out
but that's just me