Nope script improved as requested:
https://pastebin.com/yyUq0UxY
Blacklisted images get a nope css class instead of being removed.
A css rule in Theme options must be added, otherwise the script will do nothing.
I use this:
img.nope { filter: grayscale(100%) blur(20px); overflow: hidden; max-width: 150px; max-height: 150px;}
Click an image to de-blacklist it.