bug#21239: 25.0.50; `(image-size image 'pixels)` is causing Emacs to freeze on OSX Snow Leopard.

[Keith David Bershatsky]

When the variable `doc-view-scale-internally' is set to `t` in `doc-view-mode', 
Emacs tries to calculate `displayed-img-width', which looks like this:

(car (image-size '(image :type imagemagick :file 
"/Users/HOME/Desktop/page-1.png" :pointer arrow :width 850) 'pixels))

The image size can be calculated without 'pixels, but adding 'pixels to the 
equation causes Emacs to freeze -- every time -- on OSX Snow Leopard 10.6.8.

It is necessary at that point to force quit Emacs -- i.e., not even C-g can 
unfreeze Emacs which displays the spinning circle for the mouse pointer.

Thanks,

Keith

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

In GNU Emacs 25.0.50.1 (x86_64-apple-darwin10.8.0, NS appkit-1038.36 Version 
10.6.8 (Build 10K549))
 of 2015-08-04 on server.local
Repository revision: 118363 mina86@mina86.com-20141117204835-paxrwolqd1cgwtdp
Windowing system distributor `Apple', version 10.3.1038
Configured using:
 `configure --with-ns'

Configured features:
IMAGEMAGICK ACL LIBXML2 ZLIB

Important settings:
  locale-coding-system: utf-8-unix

Major mode: FM

Minor modes in effect:
  tb-mode: t
  sb-mode: t
  ml-mode: t
  ds-mode: t
  sd-mode: t
  bc-mode: t

Recent messages:
Wrote /Users/HOME/.0.data/.0.emacs/.lock
Emacs:  (car (image-size '(image :type imagemagi . . . [2 times]

Load-path shadows:
None found.

Features:
(shadow emacsbug sendmail lawlist-ztree lawlist-yas lawlist-ws
lawlist-wl elmo-imap4 elmo-localdir modb-standard modb-legacy
elmo-internal elmo-flag mmelmo-imap mmelmo-buffer elsp-generic mel-u
ps-print ps-def lpr parse-time disp-table enriched lawlist-w3m
browse-url doc-view image-mode ccl lawlist-window lawlist-vl
lawlist-view lawlist-undo lawlist-txt lawlist-tm lawlist-tex compare-w
lawlist-tabbar lawlist-speedbar lawlist-sgml lawlist-sb
lawlist-saveplace lawlist-ruler mule-util lawlist-replace
lawlist-rectangle lawlist-re-builder lawlist-python skeleton
lawlist-profiler lawlist-print lawlist-php lawlist-perl lawlist-parens
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org-pcomplete org-list org-faces org-entities org-version
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lawlist-git ido view vc-git vc vc-dispatcher url-http tls url
url-proxy url-privacy url-expand url-methods url-history mailcap
url-auth url-cookie url-domsuf url-gw thingatpt time-stamp server
log-view log-edit message mml mml-sec mm-decode mm-bodies mm-encode
gmm-utils mailheader pcvs-util add-log lawlist-help quail help-mode
json grep compile find-lisp ediff-merg ediff-wind ediff-diff
ediff-mult ediff-help ediff-init ediff-util ediff ert find-func ewoc
debug eieio-base diff-mode conf-mode autorevert filenotify
lawlist-frame lawlist-frame-bufs lawlist-font-lock lawlist-fm
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text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote make-network-process
cocoa ns multi-tty emacs)

Memory information:
((conses 16 1968786 136680)
 (symbols 48 80381 0)
 (miscs 40 131 202)
 (strings 32 179551 28304)
 (string-bytes 1 6480231)
 (vectors 16 37618)
 (vector-slots 8 911420 13879)
 (floats 8 1935 322)
 (intervals 56 334 0)
 (buffers 976 11))