After I've uploaded a picture. Let us say it has been there for a bit and there was a vote and people voted.
How can I upload an updated picture, replacing it but not lose the votes? I see an edit description, doesn't seem to be a upload a new file. I can delete and reupload it but then I lose all the votes, etc.
That's the whole point: users voted for that particular pic. Swapping it with another pic would be cheating imo. This is not possible using the regular coppermine interface. You'll have to replace the file manually (using your FTP app) - backup before you try, as you should only do this if you know what you're doing.
It is mainly for editing later. The site is used by multiple artists. So some have started to add watermarks for added security or they might of framed the image or added a sig tag to it, etc.
I made for plugin for this, look in the plugin contributions board.