Well! It's tricky, isn't it?
If that is the same blue it still looks good for
escheri, but there's nothing absolutely definitive there to say it's not common blue. The black lines running in from the margins are typical
escheri, but can be found in common. The light isn't illuminating the
escheri 'antlers' but I have plenty of pictures where they don't show, like this one (last week):
The half-chequering looks good for escheri, but again, common blue can have this and the marginal line on your butterfly is very narrow.
The next picture, of a female, looks like a common blue to me. The last picture, also of a female, lacks an obvious cell spot but isn't
escheri - could be Chapman's, which flies in the general area (you might find a complete list of the butterflies of Kos rules out Chapman's or Escher's - islands often don't have all the butterflies of a region). This is a female Escher's, again last week:
Once you have experience of them, Escher's blue and Chapman's blue are easy in the field, when you can examine all sides and angles. But it can be infuriatingly hard from photos! You might just have to go back to Kos next year...
Guy
EDIT - Ah, I didn't notice that common blue for comparison! It doesn't have nearly so marked black lines running in on the forewing, nor any half-chequering - so still looking good for Escher's...
