Untrack folder locally in git and push to production without deleting

With git rm --cached, the files are removed from git, though they're still in your local folder. So after you push, the files on sever will be deleted, and so do others' repository when they pull.

A better way is to use git update-index.

git update-index --assume-unchanged images/*

It should fulfill your requirement. The only problem is that if others' change these image files and push to git server, you will still get these changes when you pull.