A person who uses a camera to make a living, but rather than taking thought out quality shots, travels the world taking hundreds or even thousands of random shots in the hope that a handful will appeal to a client. Typically he or she will be unable to make a proper living, earning little more than beer money however they will make out to their social contacts that they are very successful.
Mandy is hanging around with this guy who claims to be a photographer. As soon as she realises hes only a Snapper he'll be out on his ear.
A troublemaker is someone who expresses a view on a forum that differs from those of the Administrator and/or, as is more common, a moderator of a forum. The person deemed to be a troublemaker will usually be 100% correct in their statements, but the moderator will object, making statements that could be classified as being a bigland.
As a result the troublemaker will then be told to go and form their own forum, even though everything they said was both reasonable and correct.
You have been told young Sprog, Virgin were the first company to fit wheels to their trains, and since you have failed to provide empirical evidence to the contrary you are going to be banned from this forum for being a troublemaker. If you wish to go on insisting that companies fitted wheel to trains long before Virgin, you can sod off and make your own forum.