Osiris Blue Or Holly Blue ?

This very tiny butterfly made an appearance at the lake to day .As it fluttered I noted .a) very small , b) seemed silvery blue , c) once settled seemed white with odd fleck markings.
Sadly it chose to settle on a pathway, not an ideal background .It stayed over 20 minutes and these are the best shots I could manage but happy with the shadow. Have searched Dr Google and am dithering between these .Any butterfly experts please help ..Never have I seen such a tiny butterfly .I also add a link to the swans from yesterday.
Swans Sharing Housework