How do you plan on enforcing the no-NSFW policy? That seems close to impossible pre-monetization unless you spent most of that year training a neural network.
Could always use https://www.projectoxford.ai or something like it. I know Google just came out with an API for generating text descriptions of images. Perhaps if scanned images passed through this api were tagged with certain words, the images could be marked for moderation and not shown until approved.