Gabriel Wyner recommends, in its Fluent Forever book, that each Anki note (card) has at least one image associated to it. This is intended to improve overall retention.

Back when I started my German Anki deck for language learning, I did not add any images. Now I find myself slowly backfilling my already existing notes with images. However, the more images I add, the harder it becomes to find notes without images.

Upon reading the Anki manual I figured out a way to find out which notes are still missing images:

  1. Open Anki.
  2. Open the deck you want to modify – in my case, Languages::German.
  3. Click “Browse”.
  4. Type in deck:current "Front Example:".

“Front Example” is the name of the field of my note template wherein I add images; you should replace it with the corresponding one you use. This syntax isn’t intuitive at all. Initially I was trying something like -"Front Example:*".