But they don't always have custard in, they can be savoury, and are still called flans.
The name of the picture is "flan tart" which would be accurate here, if it's a flan flavored thing made in a tart pan. But the thing that's on the plate with the caramel sauce is a flan, which you call crème caramel.
In Europe a pastry lined tart with a custard based filling is also either a quiche, flan or a tart.A savory thing would have a different name here. If it had a pastry bottom ad open top, but not with a custard filling, it would be a tart. If the filling was mainly egg it would be a frittata. If it was egg+cream, and had a pastry bottom, it would be quiche.