This one photo tells you all you need to know about Syria

Yet the context is as important as the timing. On Wednesday Putin is due to welcome Iran's Hassan Rouhani and Turkey Recip Tayyip Erdogan -- a noticeably small list of guests that leaves out the US and Europe -- to the same Black Sea resort to discuss a political settlement in Syria.

Here, on Monday, he met with Syria's Assad -- a man widely recognized as behind the deaths of thousands of his own citizens, but now, even after five years of savage sectarian warfare, the victor without many spoils.

Monday's meeting was presumably to explain to Assad what a Russian-brokered political settlement in Syria would look like, and perhaps for Moscow to hear input from Damascus before the real power brokers in this proxy war meet Wednesday to forge a deal.

Still, the dynamics of the hug are clear. Putin looks like 17 years in power have taken their toll, but he is grinning, and not "mired in the quagmire of Syria" as his detractors warned he would be when he entered the war in 2015. It should be captioned as though the war is over, even though days earlier there were reports of phosphorus being used on rebel-aligned civilians in the Damascus suburbs. You can't see Assad's face in this photograph, but this is the second time we are aware of that he has left Syria at all since the conflict began in 2011, so you can presume he's pleased about that, at least.

Wednesday sees the meeting of Turkey, Iran and Russia. Iran and Russia often have slightly divergent ambitions for regional influence, but they both seek to bolster Damascus' grip, and have done so with brutal efficiency.

The Assad regime now controls most of the cities that it practically can, or that remain standing and desirable, despite Assad once expressing ambitions to retake the entire country.

Other northwestern areas are held by Turkish-backed rebels, and in the northeast, US-backed Syrian Kurds control much of the territory.

These Sochi talks are likely to spell out these internal borders. But they will also address Turkey's ambitions for the awkward northwestern part, where Syria's tormented and disenfranchised majority -- its Sunnis -- have a homeland of sorts.

There, Idlib has become a home to many extremists, but also tens of thousands of civilians, some still under bombardment. These talks will presumably lay out how far Ankara is willing to go to enforce a cessation of hostilities between regime-held areas and those parts of the north controlled by rebels. But there are some crucial actors missing from the picture.

What's not in the picture

Firstly, the Syrian Kurds aren't there, and aren't invited on Wednesday, as far as we know. That would make sense as Ankara has labeled them terrorists, because it is at war with Kurds along Turkey's southern border. But the Syrian Kurds have had a comfortable enough relationship with the regime and control the vast swath of northeastern Syria that ISIS has been vanquished from (with American assistance). A key question is whether the regime is happy for a city in this area as important as Raqqa to remain in Kurdish hands for now, and how Iran or Turkey feel about that too.

Secondly, there is one country not in the picture, or at the talks, that used to be considered indispensable in such geopolitical arrangements, and that's the United States.

Putin and Trump spoke many times recently in Vietnam, and issued a joint statement on Syria, agreeing that their efforts would continue "until the final defeat of ISIS is achieved."

The State Department -- which a spokesman recently admitted was suffering low morale owing to heavy staffing shortfalls -- has insisted there have been "intense, difficult" negotiations over this statement.

But it is a joint statement over an issue that has seen Moscow and Washington at odds for six years. And it is Putin who will apparently call Trump on Tuesday to report back on his meeting with Assad. The US has always been inconsistent and reluctant in its approached to Syria's war, outside of defeating ISIS.

But on Wednesday, it won't even be in the picture.