screenshot.el

(defun bci/--screenshot-to-image-format (type)
  "Save a screenshot of the current frame as a TYPE image, with
  the appropriate file-extension.

  TYPE should be given as a quoted symbol, as it is passed directly
  to `x-export-frames'.

  The result is saved to a temp file, with the filename placed also
  in the kill-ring."
  (let* ((file-extension
          (if (eq type 'postscript)
              ".ps"
            (format ".%s" (symbol-name type))))
         (filename (make-temp-file "Emacs" nil file-extension))
         (data (x-export-frames nil type)))
    (with-temp-file filename
      (insert data))
    (kill-new filename)
    (message filename)))

;; Wrapper for convenient interactive usage
(defun bci/screenshot-to-image-format ()
  (interactive)
  (let* ((table '(("svg" . svg)
                  ("pdf" . pdf)
                  ("postscript" . postscript)
                  ("png" . png)))
         (choice
          (cdr (assoc (completing-read "Format: "
                                       '("svg" "pdf" "postscript" "png") nil)
                      table))))
    (let ((filename (bci/--screenshot-to-image-format choice)))
      (if (y-or-n-p "Preview?")
          (find-file filename)))))

(bind-key "C-<print>" #'bci/screenshot-to-image-format)