(image-type-header-regexps): Use only JPEG magic number

to determine JPEG images, and don't use `image-jpeg-p' because
Emacs can display non-JFIF non-Exif JPEG images.

lisp/ChangeLog

+2009-08-28  Juri Linkov  <juri@jurta.org>
+
+	* files.el (magic-fallback-mode-alist): Add ZIP magic number
+	associated with `archive-mode'.
+
+	* image.el (image-type-header-regexps): Use only JPEG magic number
+	to determine JPEG images, and don't use `image-jpeg-p' because
+	Emacs can display non-JFIF non-Exif JPEG images.
+
 2009-08-28  Juanma Barranquero  <lekktu@gmail.com>
 
 	* arc-mode.el (archive-mode):

lisp/image.el

@@ -43,7 +43,7 @@
 static \\(unsigned \\)?char \\1_bits" . xbm)
     ("\\`\\(?:MM\0\\*\\|II\\*\0\\)" . tiff)
     ("\\`[\t\n\r ]*%!PS" . postscript)
-    ("\\`\xff\xd8" . (image-jpeg-p . jpeg))
+    ("\\`\xff\xd8" . jpeg)    ; used to be (image-jpeg-p . jpeg)
     (,(let* ((incomment-re "\\(?:[^-]\\|-[^-]\\)")
 	     (comment-re (concat "\\(?:!--" incomment-re "*-->[ \t\r\n]*<\\)")))
 	(concat "\\(?:<\\?xml[ \t\r\n]+[^>]*>\\)?[ \t\r\n]*<"