While I admire his crystal ball, this picture itself is nothing. De Ligt would have agreed to take picture with a fan wearing a PSG, Manchester United, Juventus or any jersey for that matter. It means nothing.
The whole thing was about how funny he predicted that event with pinpoint perfection. Not that it matters in the transfer.
As de Jong transfer has shown, all those small evidences people tried to find amounted to nothing. When the player made his choice, all the news came out in few hours and it was done. Just don't try to find circumstancial evidences anymore.