I think since the last android update i can not see jpg-images (full screen) on my two android devices (Motorola and Nexus) from different nextcloud instances. There is only a black screen. Is it a bug or a feature?
I cannot confirm that behavior. I just tested it with the latest Nextcloud app version 3.11.1 on Android and all jpg files have been displayed correctly.
I solved the problem. I deleted and reinstalled the android app on both devices.