Doc-view failing to generate image

[Edward Lilley]

Hi all

I'm getting a funny error when trying to open (simple C-x C-f) PDF files
in doc-view mode. The png appears in /tmp/docview500/foo, but then the
image doesn't actually appear in the buffer -- and then *Messages* shows
the error:

ImageMagick error: NoDecodeDelegateForThisImageFormat
\ `/tmp/docview500/obsmltest.pdf-07534b262c8761286817c76762acef2c/page-1.png'
\ @ error/constitute.c/ReadImage/550 [2 times]

(line breaks added)

...which is a bit baffling.

Any ideas? Poking around in doc-view.el left me none the wiser (it seems
the above is an ImageMagick error, but I can't see exactly where
doc-view calls an ImageMagick program)

Using: GNU Emacs 24.2.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.4.4)

thanks,
Edward