They are indeed a legitimate company. If I recall correctly they are on one of the composite boards of small companies that share information. If the job is of interest, follow the links and chances are they will have you register with New Image at that time.
I've done 10 shops for them this month. Tomorrow is payday. As long as that goes through, it was an easy company to work for. I was recruited the same way you were. An email. Everything I've read has been positive.