The picture of the C130 shows fuel draining from the Fuel Jettison nozzle and NOT the fuel vent system. On the Herc the fuel vent system outlet is actually underneath the wings via 2 outlet manifolds (you can just make them out in the picture approx 10 feet inboard from the wingtip). This phenomenon on the C130 was quite normal after having landed from a flight where fuel jettison has taken place. When fuel jettison takes place the Fuel Jettison pumps from each of the tanks pressurises the Fuel Jettison manifold which runs along the length of both wings. In the outboard drybays (behind the outboard engines) there is a Wingtip Jettison Valve which when selected open by the Flight Engineer opens the valve and the pressurised fuel is ported to the nozzle in the picture.
When fuel jettison is complete the Jettison pumps are selected off. However the Jettison manifold which runs the length of the wing is now filled with unpressurised fuel. The Flight Manual states that 'if time permits and it is safe to do so cross-control the aircraft to remove the excess fuel from the manifold'. After having done this the FE
closes the Wingtip Jettison Manifold Valve. However ther is still always some residual fuel left over and after landing it was normal to see a small amount of fuel drain out due to wing droop and taxying around corners.
Whether this is the reason for the fuel draining from this aircraft as I've described above is debatable, as the wing flaps are in the Take Off position and the APU is shutdown (which would indicate they may be taxying for Take Off), however the flaps may be on their way up when the picture was taken and the APU yet to be started??