[R] importing bitmap images to R

[Michael Wolosin]

All -

I'm creating some plots in R that I would like to overlay on images that 
are created outside of R.

I've used "image" before to plot image-like data within R, and have added 
vector plots on top of them, but I can't find a way to read in an external 
bitmap file into R and use that.

Currently the external files are .png's, but I could generate a few other 
types, if something else might be easier to import.

Thanks,
-Mike