Try this:
library(png)
#Replace the directory and file information with your info
ima <- readPNG("C:\Documents and Settings\Bill\Data\R\Data\Images\sun.png")
#Set up the plot area
plot(1:2, type='n', main="Plotting Over an Image", xlab="x", ylab="y")
#Get the plot information so the image will fill the plot box, and draw it
lim <- par()
rasterImage(ima, lim$usr[1], lim$usr[3], lim$usr[2], lim$usr[4])
grid()
lines(c(1, 1.2, 1.4, 1.6, 1.8, 2.0), c(1, 1.3, 1.7, 1.6, 1.7, 1.0), type="b", lwd=5, col="white")
Below is the plot.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…