Add translation variables for image handling in musdb

backend/hsb/action.json

@@ -95,6 +95,7 @@
         "preview": "Vorschau",
         "online_usage_museum": "Online-Benutzung (Museum)",
         "stats_instance_contents": "Datenbankinhalte: Gesamte Instanz",
-        "video_conference": "Video conference"
+        "video_conference": "Video conference",
+        "image_choose": "Select an object ..."
     }
 }