This is how I do what I think you are describing. I just take off the
extension, and let (pdf)latex pick the extension it wants.

(defun ox-manuscript-remove-image-extensions ()
  "Removes .png extensions from \includegraphics directives in an
exported latex file.

Run this from an org-buffer after you have exported it to a LaTeX file"
  (interactive)
  (let* ((org-file (file-name-nondirectory (buffer-file-name)))
         (tex-file (replace-regexp-in-string "org$" "tex" org-file))
         (tex-contents (with-temp-buffer (insert-file-contents
tex-file) (buffer-string))))
    (message tex-file)
    (with-temp-file tex-file (insert (replace-regexp-in-string
                                      (concat "\\(\\includegraphics"
                                              "\\(\[?[^\].*\]?\\)?\\)"
      ;; match optional [stuff]
                                              "{\\([^}].*\\)\.\\(png\\)}")
                                      "\\1{\\3}"  tex-contents)))))



John

-----------------------------------
John Kitchin
Associate Professor
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
http://kitchingroup.cheme.cmu.edu



On Thu, Apr 24, 2014 at 8:46 AM, Leu Zhe <lzhes43@gmail.com> wrote:

>  I am using org-mode to write some article now. Org-mode is really a great
> tool to outline a article with great table and image support.
>
> Org-mode can display inline .png image but not .pdf file. Because now
> org-mode can not control the width or height of shown inline image, so i
> use matplotlib to produce low dpi .png image in PNG folder for inline
> display and higher dpi pdf image in PDF folder for finally article export.
>
> In .org file, the image link is like [[file:PNG\*.png]] and
> \includegraphics{PNG\*.png}in the produced .tex file. Then emacs will use
> org-latex-pdf-process to render it to pdf file. What I want is that
> before or in org-latex-pdf-process, a regexp replace function is added to
> replace the \includegraphics{PDF\*.pdf}, and then produce the final pdf
> file.
>
> Can anyone give a hand?
>