I have seen this one in the Alps and Pyrenees, and in Southern France. However, all these photos were taken in England, where it has declined much in the past 50 years. 

 

To separate it from the Small Pearl is not tricky with an underside view, but from the top-side, look for the black post-discal spot in S2 of the forewing. It will be approximately equi-distant from the spots inside and outside it.

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One hopes for partially cloudy warm day with sunny spells to have a chance of them settling long enough for a butterfly photograph.