The first and third graphs inverse will still be functions (although the first is iffy as it is hard to tell if when any x values are equal, if there are equal x values it will not be a function because then there will be multiple y values for a single x value. In simpler terms, if there is a truly horizontal line in that first graph, its inverse will not be a function as it will fail the vertical line test.)
The second graph will not be a function as each x value will have two y values, so it fails "the vertical line test".