Starfleet Academy is a four year course, right? We saw Picard with hair after he graduated and was awaiting assignment in "Tapestry". He was in the usual maroon dress uniform of the era.
The pic in Nemesis shows Picard in the cadet jumpsuit, giving up to FOUR YEARS for the guy to grow his hair back after having shaved it off.
In a similar real-life story, I used to shave my head but I don't anymore. This complaint probably is the most pathetic and stupid one in ALL of Star Trek.
Heck, even taken as a simple rewrite, making Picard bald at the age Patrick Stewart was (19), it really doesn't matter. Certainly not worth the fuss made here and in other threads.