When the atmosphere of an image is thick with sadness, misery, and desperation. Bonus points if you are emotionally moved, especially if you're an avid abuse fan.
This is not (specifically) for when you personally feel sad that something is happening but for when the visuals, shot framing, and text reflect the artist's desire to create a depressing scene. Note that yukkuri in distress may not be specifically depressing (see every pic tagged with abuse, for instance).
For more yukkuri in despair, see the link.