One thing I have been tinkering with recently is the ability to create R plots as KML. This is implemented in the RKMLDevice package on Omegahat. One creates a regular graphics device with the function kmlDevice() and issue regular R commands to generate the plot. One can then display the resulting document in Google Earth (either stand-alone or the browser plugin) and the R plot will appear centered at the coordindates specified when creating the device. This is not a PNG image, but the graphical elements in the plot are regular KML elements, i.e. Placemark elements. This means they scale well. Also, they appear in the Folder for the plot and one can toggle their visibilities. There are some examples at http://www.omegahat.org/RKMLDevice/examples.