VM needs to use insert-file-contents to insert file contents into MIME messages. If VM inserts an image, image-mode kicks in because of all the stuff heaped on format-alist. This breaks VM. I could use insert-file-contents-literally and have been doing so until recently, but this means EFS no longer works for retrieving files to be attached. So I'm stuck. I think image-mode is hacking into the file reading code at too low a level. The image-mode mode stuff ought to be removed from format-alist. image-mode's type detection stuff should be able to work as a find-file hook. At that level, it won't interfere with insert-file-contents.