Here are two photos of blue butterflies for the colour theme of the day, indigo-ish enough I hope. Both are males; the females of the species are not nearly as blue, or even blue at all.
The common blue (Polyommatus icarus):
The silver-studded blue (Plebejus argus):
Nice and blue, aren't they? From the side, these two species are not blue, but easier to tell apart; check for the little blue specks.
The common blue (Polyommatus icarus):
The silver-studded blue (Plebejus argus):
And another photo, because I can:
Thanks for watching!
All photos made by me.