there are a lot of schools of thought on this subject, some people agree with it whole heartedly and others don't believe it at all...
i once got a picture of my aura taken, it was very red lol and some of what the man explained about my aura made sense and a lot of what he said didn't...
i guess it is up to interpretation...
and on the colours and their meanings, one colour can have many different meanings depending on what you read.
i would suggest doing some research on people who do readings in your area and find someone credible and go and see them...
hope this helps :)