Help ! Uploaded photos replace new ones

[BigChocFrenzy]

When I upload a photo, it replaces all but one of the earlier ones. Strangely, my uploaded photo is then displayed 2 or 3 times in my MN photos

I've tried saving the previously uploaded photos in different positions - top, bottom, in between, but to no avail, they disappear when I upload fresh ones.

I tried via iPad 2, iphone 5S, PC. I didn't use the MN App, because I didn't see how to get to my profile.

Any advice, please ?

I now see that even my existing public photo is now not visible in my profile. The message where the photos should be is "Sorry we couldn't find that photo"

I could upload and display photos in October and November, no problem. I haven't changed anything at my end, re hardware / software.
Now, even my old photos from then won't upload.