I would check the state's or province's rules for that. It may vary, but usually you must keep some portion that identifies what sex the game was, and of course keep the tag. Should keep the rack too, to prove it was legal. In most states when transporting game, the tag must be attached to that game animal, regardless of whether its gutted, skinned or butchered.
As Cowgal said that would be a provincial law. Saskatchewan uses a two-tag system, for every licence you're issued a meat seal and a head/hide seal. The meat seal must remain affixed until butchering, the head/hide seal must remain affixed until min 31 Mar.
Everyone has different ideas about trophy pictures. Looks around and you will see "long armers," "set behinders," "big cheesers," and "blood covered brutes." I have a few tips to keep your trophy pictures from being laughers or worse yet just plain gross.
#1 Clean it up. Try to avoid bullet holes, gut pile, mass amounts of blood, and the tongue sticking out. You don't want your big buck to look like a angry 1st grader with his tongue out or a MMA fighter during the 3 round.
#2 Long arming...