How to adjust the size of R plot imported with get R graphics(); ?

[#1]

I'm trying to run R code in JMP to create a plot. I succeeded in importing the plot in png format, but failed to adjust the size of the plot.

I can adjust the "plot_from_R" in png format with the set size(); function in jsl, but it is not proportional and distorted.

How can I import plot_from_R in the size I want?

R Init();
R Submit(
	"\[
windows(300,100) #it doesn't work
plot(function(x) dnorm(x), -5, 5, main = "Normal(0,1) Density")
]\"
);
plot_from_R = R Get Graphics("png");
plot_from_R << set size({600, 200}); //it works but the plot is distorted (out of proportion)
New Window("plot_from_R", plot_from_R);
R Term();