Yeah, it's probably the gratuitous secondary sunburst being drawn into the background of that demo page. That's a pretty big PNG image (i.e. the size of your vi

Yeah, it's probably the gratuitous secondary sunburst being drawn into the background of that demo page. That's a pretty big PNG image (i.e. the size of your viewport) being generated. For smaller uses it shouldn't be an issue, but gratuitous use will definitely cause performance problems.