I enabled "save images to server" for a short time while we were getting our forum set up since it appeared that the forum software didn't accept the php url for avatars. Once we got that working, I disabled that option but when I do an update I still see "saving signature/saving avatar" in the log. I've checked the site and it appears that the files aren't actually being saved, but this is still something that can cause confusion.

Are you sure you have it really turned off?

You have to change the setting for signatures and avatars and turn off save on character update and guild update

I've confirmed that all three options are off (though it seems odd that setting "Save images to server" wouldn't turn the other two options off, as you can't even see them unless "Save images to server" is on).