I tried to send pictures by email using the plugin. The setup is a bit weird as I have to select the mail program by hand. Next, I can't specify parameters (open kmail without parameters may not making sense if not supplied by digikam, e.g. --composer) So get this working I tried to add a (executable) bash script to /usr/local/bin (kmail_new_mail) containing: #!/bin/bash /usr/bin/kmail --composer As a surprise, digikam copies the selected binary to /run/user/1000/doc/xxxxxx and run this. I would exepect that is will execute the program directly. Unlikly it seems that kmail is not started, as no window pops up.
Of course we start KMail directly, I actually use this more often. It just doesn't work in Snap or Flatpak packages, because of the sandbox, which we have no control over. Use our AppImage. Maik