Happens to me aswell. Suddenly the list of subscribed communities is empty.

Works fine for me in Voyager. Long press the image, then select „Save to photos“.

This is the 7th (!) Lemmy App on my phone and if you ignore the fact that you can’t post, it is already the best in this first testflight build in my opinion. Renders super quickly so scrolling is lightning fast. And it is very pleasing for the eye. Looking forward for the next builds!