The effect is even more pronounced in the front view of the A3D Skywarrior because its wing is not only mounted at an angle of incidence, it has a higher aspect ratio.
Taper in airfoil thickness between the wing root and tip can also create an illusion of anhedral/dihedral or mask it. An example is the A4D Skyhawk. It looks like it has no dihedral. In fact it is almost three degrees. (Note that aerodynamicists do not measure dihedral with respect to either the upper or the lower surface of the wing. It is generally defined with respect to the chord line; in the case of the A4D, it is measured at the trailing edge of the wing.)
Some airplanes do have anhedral in the wing, of course. The F8U Crusader is one, although the actual angle might be exaggerated by the sit of the airplane relative to the camera and the raising of the wing for takeoff and landing. (You'll also note that the horizontal tail appears to have no dihedral.)
In this case, a front-view drawing can be relied on since the wing is mounted a zero angle of incidence.
Aerodynamicists also define wing-sweep angle in a very specific and even more non-intuitive way. It is not measured at the leading edge as you might think, but generally at the quarter chord, or 25% of the local chord back from the leading edge of the wing. In accordance with this convention, the A4D has a wing sweep of about 33 degrees, somewhat less than the sweep angle of the leading edge.