Asking for a preferences option:
[_] Prompt to confirm image delete
on or off. If on, current behavior. If off, PL simply deletes the image. (which ends up in the Trash bin anyway so it can still be pulled out if deleted in error)
Is that the behaviour if the image is on a network drive? In other software if I delete a file from a connected NAS folder it is permanent (I think) - that would worry me a bit
I’m also working sometimes (when I have to revisit one older raw migrated from C to NAS) and I confirm that one deleted from the NAS the dustbin is empty… 
But I agree with this request anyway (option in Preferences) as I also have a second backup in which I can search…