If you are unlucky, you might get this nasty error message.
It means that Piktures does NOT have the right to write on the file system. This could be due to multiple reasons:
A - Your file system is almost full.
For instance, you might want to delete some photos from your SD card. The SD Card has plenty of space while the phone memory is running low. This happens when you are deleting photos from the SD card and the recycle bin is activated. The operation creates first a copy of your SD card photos to the phone memory. If the phone memory is not large enough, this error message will appear.
Another example is when you want to delete files from the phone memory. It still tries to create a copy before deleting from the source folder.
Recommendation: Use a file manager to clean up the file system in order to have at least 50M of free space on your phone memory.
B - The permission to the file system is no longer granted
Updating Android or updating Piktures might cause the file permission to be revoked. This happens a lot on OnePlus devices. We don't know yet why this is happening and what to do about it.
Recommendation: Uninstall and reinstall Piktures.