
The article claims that photo experts can offer no explanations for the spectre. By looking carefully you can see that the "head" is just another part of what was an elongated shape, offset due to being projected onto a foreground pillar.
Since the pillar is curved, we know that the light source cannot be to the left of the pillar (since the light is on the right), and there's a wall to the right, so the most likely place for the light to be coming from is from roughly in front of the camera. If that's the case, then there should be quite a bit of light on the heads of the people near the bottom of the image. Is there? Let's take a look!

So while I'll agree that we can't say precisely what object caused this, it's nothing amazing. But it seems that some people, when presented with a lack of evidence, will automatically conclude it's supernatural.
However, what I really want to know, is that if there were hundreds of people there, why did not a single person notice this supposedly divine presence until afterwards, when the image was downloaded to computer?
It would seem that angels need to work on their PR department.