Hey,
I created a new userscript that hides adult content from profile galleries ([username].newgrounds.com/art).
You can check it out here: https://github.com/cyan-gorilla/userscripts/tree/master/US_AdultContentRemover
To install it, just go to the .user.js file and click on Raw. If you have Tampermonkey or Greasemonkey installed, it should prompt you to add it.
It's quite the rudimentary script, but it does the job well. Basically it first removes all elements that are marked as M and A. After that, whenever more elements are loaded (you scroll or click Load More) it checks if they are M or A and removes them accordingly.
Cheers!