At 3 months there isn't a whole lot of grooming to do...just get him used to a weekly bath and his brush, maybe shave the top 1/3 of the ears so they will stand and look neat, trim around his feet so they don't look shaggy and keep his private areas trimmed and clean. Oh, a personal tip for the boys is not to cut the long hair off their 'winkie', just leave a little bit on the end...it acts as a funnel and will keep them from getting their sides all wet when they start lifting their leg. Now, if you have him neutered before he starts lifting then he might always squat to go pee. Probably more than you wanted to know, huh?
As for pictures...at this age they're so darned fast that it's hard to get a decent picture unless they're sleeping! Sometimes you can catch them off guard but my boys either look away or take off when I get the camera out. Now that they're getting older they are getting a little better...but I still have more bloopers than good pictures!