The Iranians have a smart glide bomb. Four of these can be carried on a single drone. The display of the wreckage seems to show parts of these glide bombs. They look like short, stubby rockets. The four round tanks look like they were all hit by something fired from the same place. Iran is close enough to allow direct control of the most advance Iranian drone but Yemen is to far away.
Can you give a link to any pictures of the sites that give any indication of a glide bomb, I'd like to see that. The direction of the attack on the tanks was from the WNW, but that doesn't mean much.
Even if you were to take into account islands in the Gulf owned by Iran, the closest is over 100 miles away from the closest of the targeted sites. In order to guide a drone via optical link, you need to feed the video to the operator and that means UHF frequencies which in turn means line of sight distance of transmission of the video feed. Line of sight is will be under 20 miles for something within 100 feet altitude, which the drone would need to be in its terminal phase. So the flights could not have been directed from Iranian territory.
That part of Saudi Arabia is the Shiite inhabited part of the country and frequently experiences acts of rebellion against the Saud family's interests. So it is not impossible that the drones were controlled from a location inside Saudi Arabia (if they were in fact guided via video link).
It would also be technically possible to have controlled the drones from an aircraft anywhere within about 200 miles of the targets. But such a plane would have been visible to radar and anyone looking back on their radar logs would be able to identify such a suspicious flight. If that were the case, I think we would have heard about it by now.