Hi markwmsn - I took the photo with the Camera App and then shared it to Facebook. The signal was not very strong so I got a message to say that the photo would be uploaded to Facebook when the signal was strong enough. I was fell-walking at the time and it's possible that it didn't get uploaded for several hours until I was able to get a wi-fi signal. I downloaded a copy last night from Facebook but the file was only 66Kb. Amazingly I've now re-checked my Photos library - and it's there! So, either I couldn't see for looking (but I was quite methodical about it) or whether creating the download from the Facebook page has done something to get the original into the library I don't know. If it was the first, then I apologise to you for wasting your time but many thanks for your interest anyway.
I checked my Facebook settings and find that I have allowed access to my Photos library (and to everything else!). I wasn't aware that I could take a photo from within the Facebook App. This is probably of academic interest since I don't very often post to Facebook anyway!
Anyway, problem now solved so thanks for your help once again. Jack
