talkmagic.co.uk

by mixing first the envelopes and then the photos the odds of 1 in 3 are increased. any phot can go in any envelope

That would only come across if that was explained to the audience. In truth you still have a 1 in 3 chance of getting it first time.
you have 1 photo, which can go into any one of 3 envelopes, the point of the effect boils down to you finding that one photo.

Can I suggest we await further details before getting bogged down on what might be a relatively minor aspect or which may even be essential to the working of the routine?

Did this ever carry on? I thought it sounded pretty cool.