What I see is two people coming back from the pool after a morning swim. The mark on the wall is IMO a reflection of the lady. It isn't a shadow as there is not enough light to form shadows.
If I'm right that it is a reflection off a relatively rough surface, then the angle of incidence = angle of reflection. Then if we can work out where the person who took photo was standing then because the "image" appears to be on a line directly below end of the wall of the apartment we could make the calculations of where they are standing in the photo.
They are just past where 5A wall finishes its projection into the footpath. Measure that on Google Earth and you will find that it measures over 10 metres from the route going eastwards along the pavement.
Try not to forget that the end of the wall on that image is not at the pavement from which Tannerman appeared, because the wall has a great big curve on it, and the end is well out of sight around the bend. From measuring GE it appears thaty the bend is about 3 metres radius.
From Janes memory of it, Tannerman walked straight across the top of Rua Francisco Gentil Martins. He didn't come around the curve of the wall at all.
Thinking more about it, if Jane identified 5 metres distance between her and the man, then those two people are way lower down the road than Jane was when she saw Tannerman. I think that she would have been about 5-6 metres higher than that couple.
I do understand why the one side of the discussion is trying to persuade readers that Jane was lower down the road than it appears she was. It is an attempt, it seems, to re-inforce their argument that Janes Tannerman was not actually an abductor, but was Crecheman.

I wonder why?