How do I set my review images as 18+? There doesn't seem to be any option in the menu of doing so when you go to set a review
Now, when you submit an image, it will be auto-scanned and appropriate tags applied. If you see all grey tags, the image is SFW. If there are any red tags appended to your image, it is now considered NSFW and will be excluded from the SFW filtering.
You can "upvote" and "downvote" particular image tags, if you feel they have been applied inappropriately.