1. Create one of each question type, adding an image to every HTML editor on the question editing form. (Well, ideally that is what you would do. If you can't be bothered, add an image to at least one hint for every question editing form that has hints.)
2. Move all those questions to a different context in the question bank. For example, move the question category that contains them from the course level of the question bank to the quiz level, or to the system level.
3. Verify that all the images in the hints are still there.
4. If you are able, then delete all these questions, and verify that the corresponding files are gone from the files table. However, I think the only way to verify that is to look directly in the DB.
1. Create one of each question type, adding an image to every HTML editor on the question editing form. (Well, ideally that is what you would do. If you can't be bothered, add an image to at least one hint for every question editing form that has hints.)
2. Move all those questions to a different context in the question bank. For example, move the question category that contains them from the course level of the question bank to the quiz level, or to the system level.
3. Verify that all the images in the hints are still there.
4. If you are able, then delete all these questions, and verify that the corresponding files are gone from the files table. However, I think the only way to verify that is to look directly in the DB.