Strange photo at the cemetery

I took this shot rather quickly and didn’t look at it till I got back here.

We were visiting Mylor (Cornwall, UK) cemetery and I thought I would take a shot of my wife and father-in-law standing by the grave of her mother/his wife.  It was an overcast but sunny day, plenty of light for well exposed photographs, no glaring sunshine to throw off the meter.

Having taken the photograph in suitable lighting conditions, as I have with others on the N95, I got the following: