Is this Safe or Semi-Grimdark? It looks like Luna's being tortured or choked by magic here. I'm not really sure what's going on.
What makes it weirder is the comment section has people using spoilering as if the image was Safe all along; maybe people didn't notice what it was actually rated in the tags.
grimdarkspecifically calls out PTSD events as being its purview, and there's plenty around with that this will trigger.
Derpibooru costs over $25 a day to operate - help support us financially!