Get range of a Graphics object

Question

Let

g1 = Graphics[{Orange, Disk[{0, 0}, {3, 4}]}]

It is clear that the g1 can be contained in a rectangular region
whose left-topmost vertice and right-bottomost vertice are {-3,4} and {3,-4}.

Can we create a function F1 such that F1[g1] becomes {{-3,4},{3,-4}}, i.e., a function that yields the range of the graphics object.