Most posts with wiz_(konosuba) are tagged lich, and most posts under lich contain her.
While she is called a lich in the story, she has no visual traits of one (i.e. an undead/skeletal sorcerer), so I'm asking if it's okay to mass-remove the tag from her images.

That would be in accordance with our tag what you see policy. Unless that has been overturned by now.

Tagging characters based on their canonical attributes rather than visual appearance is a terrible idea and should be discouraged as strongly as possible. It's like tagging every instance of morrigan aensland as succubus or kanna kamui as dragon girl. Here's +1 for cleaning up lich. Also, a wiki that distinguishes lich from other undead like zombie and mummy would be helpful.

If she doesn't look like a typical lich or isn't doing lich things, then yeah take off the tag.