Young people do stupid things - that's a fact of life.
Because a young footballer does a stupid thing - thanks to modern technology, his stupidity is there for the world to see, but that does not turn him into a negative role model, it simply amplifies his stupidity.
The approach should be to make the playerapologise publicly, with a speech about the risks of guns and the futility of gang culture - and fine him a month's wages and donate the money to a local youth service, again with publicity attatched.
But let's not get too carried away here - his behaviour was stupid and thoughtless, and he should be aware that as a sportsman, his behaviour is always open to misue and manipulation - but that is about education, not punishment.
Since no law has been broken, that's as far as things should go - i am sure the player will be more careful about being photographed in the future.