I believe it is b. It was setup today. The rest of the grass is very high which could explain the grass settling around the Rum barrels. The spider web is misleading as a web can be built fairly quick and his tent was probably setup first as he has already unloaded and crashed. The bedroll on his back and no campfire are good clues as well as the ship leaving. Not to mention the man in the water in the background who seems to be still pulling stuff in out of the water.
b) The spider web would make you believe it was there overnight, but there is no campfire or other signs of use. The solider searching still has his bedroll on his back. The Spaniards left in a hurry or they would have taken their flags with them.
I'd say today. Tent is too clean. No fire. Grass could have been overgrown already. Plus if the camp had been there for awhile the grass in front of the tent shouldn't be so high. It would be trampled on constantly. Plus the tent in the back is empty and the guy with the musket has his pack still. And the other one must have put his clothes in the tent to bathe after being at sea for days