Need help in correct identification of this small grass blue butterfly. To be more specific what is this butterfly, tiny grass blue or pygmy grass blue or pale grass blue?

Here is the image.

Here are images of each:

Image Search Results (http://www.goodsearch.com/searchimage.aspx?keywords=grass+blue+butterfly)

Image Search Results (http://www.goodsearch.com/searchimage.aspx?keywords=pygmy+grass+blue+butterfly)

Image Search Results (http://www.goodsearch.com/searchimage.aspx?keywords=pale+grass+blue+butterfly)

Distinguishing between them I leave as an exercise for the student.