Not sure if this is a bug or not, but I definitely won’t expect from Anki to delete the media I’m actively using as elements of my card templates (but NOT included in the cards themselves)
After clicking on tools > check media:
(Same is ocurring with similar templates for other languages)
PS: An easy workaround would be to include the image file as a part of one of the cards, which works, but again, I think that is not intended behaviour.
PS2: happens in 2.1.26 and 2.1.44