overplotting on png map tile in R

Dear R geo wizards,
while I am very happy with the kmloverlay() function from the maptools
package to create overlays from R in Google Earth, I often would like
to perform an even simpler task.
Given a png image with a known lat/lon bounding box, such as a map
tile or some other geographically aligned image, I would like to
(i) ?load the image into R,
(ii) plot the image, and
(iii) overlay e.g. lat/lon referenced points on top of this image

The points should be plotted with respect to the coordinates of the image.

Is this possible at all ?

Thanks !

Markus