Revert afca8f14a

Fix #2932

modules/lang/org/autoload/contrib-dragndrop.el

@@ -10,13 +10,3 @@
            (rassq-delete-all '+org-dragndrop-download-dnd-fn
                              (copy-alist dnd-protocol-alist))))
       (dnd-handle-one-url nil action uri))))
-
-;;;###autoload
-(defun +org-dragndrop-image-fn (protocol link _description)
-  "Return the image associated with the current attachment."
-  (let ((file (expand-file-name link org-attach-id-dir)))
-    (when (and (file-exists-p file) (image-type-from-file-name file))
-      (with-temp-buffer
-        (insert-file-contents file)
-        (goto-char (point-min))
-        (buffer-substring-no-properties (point) (point-max))))))