A lot of blank black photos appeared in my iCloud marked by a triangle containing a warning exclamation point.

On my 64GB iPad I'm always on the tightrope of available space.

Often, even without having managed to occupy it all, if I only have a gigabyte and a little more, the photos app refuses to load the entire image, and I have to content myself with scrolling the preview, looking at a white dot with an exclamation mark in the bottom of the image, indicating the problem.

Up to here, so good.

Today however, thanks to the fact that I still had little space, but also that I was sorting the photos into various sub-albums with an app called Slidebox, while I was sorting them I found myself again in the situation of sorting only thumbnails and not the complete photos downloaded from iCloud.

Now, I don't know what the underlying mechanics are between the Photos app and iCloud, but I assume and hope that the Photos app has correctly sorted thumbnails into the given sub-albums, and those thumbnails are still linked to iCloud Photos, which will update the paths of the individual photos.

Without thinking further, in this situation of lack of free space, I took some screenshots.

After a while, I realized that the app contained hundreds of black, undownloadable full-size images from iCloud, although now I wish I had the space to do that, because I cleaned up.

I checked iCloud Photos from the web, and there too are the hundreds of black images, matching the ones I see on the ipad, but with a big white warning triangle in the center, zero kb in size, and with no other information except the time, which happens to be the same for all of them.

So I don't know whether to think that iCloud corrupted the previous photos that I sorted, or that my iPad tried to save one or more screenshots in the absence of space, and failing it entered an error loop that created many black images equal then sending them to iCloud.

I don't know exactly what mechanism not being an Apple engineer...