Export Parametric Plot as PNG with no background

How do I export a ParametricPlot as a png image with no background? For example, my exported image look like this:

But it has a white background. I need that white background to be a completely transparent alpha channel, but I cannot figure out how to do this with ParametricPlot. Can somebody give an example using the Export command?

• The easiest way is to do Export["test.png",Rasterize[yourplot,Background->None]]. – N.J.Evans Dec 17 '18 at 18:40

Just use Background -> None inside Export . Assume that you have a parametric plot
a = ParametricPlot[{Sin[u], Sin[2 u]}, {u, 0, 2 Pi}] .
Export["tra.png", a, Background -> None] .