In an European context, vigilantes are also criminals, as the only organization which is allowed to use force is the state, which is legitimatized by the citizens.
It is easy to ignore your further points when your initial premise is instantly recognisable as utter bullshit. Use of force is not vigilantism unless it is dishing out punishment outside the law. As for the state being the only thing allowed to use force, does a club bouncer/doorman not use force from time to time to keep to defend themselves and others and to keep the peace in the club? Are you under the impression we have state-run clubs?
More detail on the UK situation if you're interested at all in the truth: http://www.cps.gov.uk/legal/s_to_u/self_defence/
One of the more inspiring aspects of this whole situation is how well some immigrant communities have been stepping up: http://www.youtube.com/watch?v=m3Hp2pOQYqk
Not that any of this has anything to do with the original post about image analysis.