Just change the pictures in cmd/anubis/static/img/ to whatever you prefer, I think.
Or, alternatively, you know, pay the author for the work they've done
Sure, if you're going to deploy it on your company site, but I think if you're running a personal website and want to throttle LLM crawlers without falsely advertising that you're a furry, you could just go and modify this piece of MIT-licensed software.
Or you could pay for BotStopper and have RPM/DEB packages too.
Or, alternatively, just embrace anime-porn content spectrum. I mean, just compare platforms that are free of it and ones that are chock full, and see which ones die and which grows.