As in the subject, the XBM image properties :foreground :background 
have no effect on OSX. 

This is easily tested with:

=========
(defun make-test-image (foreground background)
  `(image :type xbm
	  :data
	  ,(let ((data (make-bool-vector (* 10 10) nil))
		 (index 0))
	     (while (< index (* 10 10))
	       (aset data index (= 0 (% index 3)))
	       (setq index (+ 1 index)))
	     data)
	  :height 10
	  :width 10
	  :foreground ,foreground
	  :background ,background))


(defun test-images ()
  (interactive)
  (insert-image (make-test-image nil nil))
  (insert-image (make-test-image "red" nil))
  (insert-image (make-test-image nil "green"))
  (insert-image (make-test-image "blue" "orange")))
=========

After running `test-images' I expect differently colored images, but
they are all monochrome. (black and white).

After applying the following patch, it works for nextstep based terminal
systems.

I have tried to adher to the style already present in the file,
and I do not the setup is the most elegant.  But changing that
would require a more intrusive patch.


Wim Oudshoorn.