Walllet photos from printers at supermarket promotions

My son in law claims to have seen a baby photograher at a shopping centre printing out a strip of photos (babies, in this instance) that were only wallet size. Since he is going to host a "meet Santa" event for kids this year he wants to be able to do the same and is cetain it was only a typical home type inkjet printer tha was being used. It seems pretty unlikely to me since the output was aparently as a strip and not on a sheet that then needed to be cut down with a lot of wastage.
Retalers we have spoken to today know of no such thing. Has anyone seen such a printer? It's more just to settle the query that I want to know although, since my partner will be photographing the kids, it would be handy for us to know if such a thing exists since we will have to buy a portable printer for the event anyway.

Thanks,

Hal55

I know of no 'proof printers' that are designed to put a series of photos onto precut paper strips, that would resemble a strip of photos. I do know that some dye sublimation printers use a roll of continuous output paper, that is not wider than a few inches, but 3.5x5" is the smallest size individual photo to come out on a roll on the unit I am familiar with.