On a smartphone, the "idiomatic" way to send something to someone else (the opponent) is a [Share] button, rather than copy/paste thru the clipboard. I think we should add such a button: displayed for platforms that support it natively (i.e. all major mobile browsers), hidden for platforms that don't (i.e. desktop browsers).
The image card (as displayed by Whatsapp or Twitter or other) should show the board from the point of view of the Black
Observed
The image card shows the board from the point of view of the White
How to fix
I suspect that the image card generation currently only takes the state of the board into account, but doesn't take into account who was the last player. Ideally, the generated image should be tailored for the next player (the one who will have to read the board and make the next move).