Take a screenshot and insert in emacs(Mac only)

my-org-screenshot.el

(defun my-org-screenshot ()
    "Take a screenshot into a time stamped unique-named file in the
same directory as the org-buffer and insert a link to this file."
    (interactive)
    (setq filename
          (concat
           (make-temp-name
            (concat
             "art/"
             (buffer-name)
                    "_"
                    (format-time-string "%Y%m%d_%H%M%S_")) ) ".png"))
    (call-process-shell-command "screencapture" nil nil nil "-s -t png" filename)
    (insert (concat "[[file:" filename "]]"))
  (org-redisplay-inline-images)
)