Congrats on the purchase, you truck looks pretty good for the age / mileage.
as for the leak, I cant confirm where it is coming from but you will need to inspect and eliminate the following:

1. Valve cover gasket condition
2. Leaking oil pan sealant ( its not a gasket)

Mines looked exactly like yours and I changed both as I had leaks on the valve cover AND the oil pan gasket ( after a Catch can caused over pressure in the PCV) dumba$$ POS catch can BS.
One of your pictures above shows a leak on one of the oil pan bolts. recommend inspecting some more.

Prepare for a long weekend and post repair neck pain if you plan on doing the oil pan sealant replacement as you have to drop the front differential to properly access the pan for removal / replacement. There is no other way around it.