JKT, I just happen to have a thriving colony of geranium arguses in my garden so it's one of those butterflies that I can recognise instantly on jizz.
I'm sure JKT is right about the
semiargus and
argiolus (and Dave for the
argiolus).
It's true that the other male blue looks very good indeed for
dorylas. The hind margin is not as clean white as the
dorylas in Switzerland (this butterfly has half-greying) but apart from that it is classic in every way. I would certainly consider that a possibility if the picture was taken in S.E. Sweden or one of the islands off the Swedish coast. And if it was, could those female blues possibly even be Reverdin's,
P. argyrognomon?? Is it possible that is crown vetch the first one is sitting on?
The tiniest hint of a glimpse of the underside of any of them would settle the score, I think!! Tantalising!
Guy