By Jonathan Marcus
Diplomatic correspondent, BBC News
"There are three kinds of lies: lies, damned lies, and statistics."
This saying, attributed to the Victorian British Prime Minister Benjamin Disraeli, could be updated for our own times. One could speak of "lies, damned lies and satellite images".
Pictures from the "all-seeing" eyes in space have become an often-used tool, at least for those governments that have access to them, when trying to convince public opinion of the need, say, for military action.
Think back to the briefing by the then US Secretary of State Colin Powell at the United Nations in February 2003 when he marshalled an impressive array of satellite images, communications intercepts and other intelligence data to make the case that Saddam Hussein's Iraq still maintained active weapons of mass destruction programmes.
The only problem was that he was wrong. Whatever the satellite images may have shown at the time that they were taken, the overall case did not stand up in the wake of the invasion of Iraq.
So caution is the watchword when anyone uses satellite imagery to prove a case. Such pictures are nothing more than a snap-shot in time, requiring careful and expert analysis.
Of course, once only powerful governments like those in the US and Russia had access to such imagery. Today, high-powered satellites are much more common.
Many more governments have access to them, and a significant commercial sector has also developed that is producing imagery for a range of functions: charting land use, agricultural surveys and so on.
But if you have the money; if you know where to look; and if you have the expertise to analyse what you are seeing, then you too can become in effect your own intelligence analysis centre.
This, in a small way, is what the US-based think-tank the Institute for Science and International Security (ISIS) has set about doing.
Satellite imagery needs careful analysis
It is independent, it is highly expert and it has focused specifically on nuclear programmes, revealing - often with the help of commercial satellite imagery - aspects of the nuclear programmes of countries like Pakistan and Iran.
US sources have encouraged the press to believe that on 6 September Israeli jets struck at a nuclear reactor that was under construction in Syria; a reactor based upon North Korean designs.
Syria has loudly and repeatedly denied that it has any clandestine plans to build such a facility. So what light has the ISIS imagery been able to shed on all of this?
Its pictures of the alleged site of the Israeli air attack have provided the most authoritative insight so far into an operation that still remains largely shrouded in secrecy.
ISIS has produced two sets of pictures. The first, taken before the Israeli raid, show a facility near the Euphrates River in north-eastern Syria. They show what ISIS believes to have been the target of the attack.
There is a large industrial building, of a similar size to that which houses the North Korean gas-graphite reactor at Yongbyon. There is also what ISIS says may be a pumping station near the bank of the river which would be needed to provide water to cool the gas used in cooling the reactor itself.
ISIS accepts that the images are not conclusive. The building housing the alleged reactor is fairly nondescript and could be used for any number of purposes.
But the second picture of the same site, which was taken some six weeks after the Israeli attack, provides some powerful indications that this could indeed have been the target of the operation.
The building has simply disappeared. It has been razed to the ground and all traces of the facility, except for the pumping station, have been removed. The site is criss-crossed with caterpillar tracks from heavy earth-movers.
There is every indication that the Syrian authorities have moved swiftly and dramatically to remove all evidence of what was there.
Still there is nothing conclusive, but the evidence is slowly adding up. We still do not know for certain what the Israelis hit. We do not know how successful their attack was. And if this was some kind of nuclear installation we do not know how advanced it was or where the technology and know-how came from.
But all the evidence does point to one fact. The Syrian authorities, whatever their denials, certainly have some explaining to do.