Question

In an Emacs org-mode file, when I click on a PDF the file opens in a PDF viewer. Similarly, when I click on a URL it opens in a web browser. But when I click on a path to an image file, the byte stream opens as text in the editor. How do I configure Emacs/org-mode to open images with a specified application, say an image editor or a browser?

Answer 1

In org-mode, this is org-file-apps that control what to do when clicking on a URL-like text.

It is configured by default to :

((auto-mode . emacs)
 ("\\.mm\\'" . default)
 ("\\.x?html?\\'" . default)
 ("\\.pdf\\'" . default))

As said in org-file-apps help : auto-mode matches files that are matched by any entry in auto-mode-alist, so all files Emacs knows how to handle. Using this with command emacs will open most files in Emacs.

You may have image file extension configured in auto-mode-alist. You could override this alist by doing something like this in your .emacs (for example, for png files) :

(add-hook 'org-mode-hook
      '(lambda ()
             (setq org-file-apps
                   (append '(
                             ("\\.png\\'" . default)
                             ) org-file-apps ))))

With this code, when I click on a link like this :

file:///e:/jrx/emacs/image.png

It opens the file outside emacs, using the default OS program associated to this file extension.

You don’t have to change org-file-apps-defaults-windowsnt, org-file-apps-defaults-gnu or org-file-apps-defaults-macosx to use the OS default program associated to the file extension.