Hi,
Digikam is great and normally stable (using 5.9 installed under Manjaro)
Digikam crashes completely due to a bug in the digikam interface to the menu/extra/create stacked images GUI.
The tool can not be used several times, because the output file can not be created due to conflict with previous file name. The name is not changed automatically.
Workaround is to manually change the output filename before closing the GUI
see here the google doc with screenshots
https://docs.google.com/document/d/12xCExoFFBrp5rcFWkkuX8tvHiKZSIIs8rTjxBL78pDw/edit?usp=sharing
Happy new Year with Digikam 2019
Christian
https://www.flickr.com/photos/128436756@N05/