Yes replacing is an option, but did you know that when you replace it the avatar the actual file it self doesn't, the previous image stays in the image folder. 😟
I decided to increase minimum reputation to a high number before user can downvote because of malicious activities... now I wanted to clean up all the downvotes.. I know I can just remove the users but I would rather not do that right now... I am familiar changes things in DB (mongo)... is there a way to remove all downvotes made so far?
There is no built-in way to do it. You would have to write a custom script that unvotes all downvotes by going through each user's downvotes.