He may actually be licensed to do that... depends what kind of license for the images he purchased - because technically this would be a 'derivative' work (as opposed to 'outright' selling the images/prints)... so - he "may" actually be "allowed" to do that...
In which case, seems very smart. Not really the best deal for the photographer/someone who only gets say $0.25 for their image - BUT - if he is licensed to do so, then he is licensed to do so (because that may be what you are agreeing to)... I'd check to see if the license does cover 'derivative' works...