This small butterfly belongs to the family Lycaenidae, which is widespread over much of the Palaearctic. The Lycaenidae are the second-largest family of butterflies, with about 6’000 species worldwide. One third of the Swiss butterflies belong to this family and quite a number of the closely related species look very similar at a first glance.
Successful identification begins with an inspection of the top and bottom sides of the wings. Having only a side view or a top view is often not sufficient. Fortunately, blue butterflies enjoy basking in the sun, and photographic patience is usually rewarded by getting both a top and side view wing picture.