[R] How to change the margin widths in png-plots?

[Atte Tenkanen]

Hello,

I have tried to change the margin widths so that mtext (here "sd of  
consecutive pc intervals", look at the picture) and  
plot(...,xlab="bar") fits to the picture.

Here is an example:
http://users.utu.fi/attenka/margins.png

This doesn't help:
par(mar=c(5.1, 7.1, 4.1, 2.1))

And here are the commands:

png(filename="/Users/kone/Vaitostutkimus/Pictures/ 
BachBWV60_sd_cons_pc_int.png", width = 2800, height = 1200,pointsize =  
12, bg = "white");
plot(Compo_SD_succ_int_array_vector,ylim=c(0.40,1.9),col="white",xlab="b 
ar",ylab="", cex.lab=3, cex.axis=2);
mtext("sd of consecutive pc intervals", side=2, line=0,  
padj=-1.8,at=1.2, cex=3)
lines(Compo_SD_succ_int_array_vector,col=1,lty=1,lwd=2);
text(2,0.93,labels="*",cex=3) # "an asterisk..."
dev.off();

What do I do next?

Atte Tenkanen, Turku Finland