Hi!
This is how I created my abatar!
library(grid)
library(jpeg)
mfig <- readJPEG("mfig.jpg")
#plot and rasterImage
x <- y <- seq(10,20,by=.5)
step <- diff(x)[1]
xrange <- range(x) + c(-step/2, step/2)
yrange <- range(y) + c(-step/2, step/2)
plot(x, y, ann=FALSE, xlim=xrange, ylim=yrange, xaxs="i", yaxs="i")
rasterImage(mfig,xrange[1], yrange[1], xrange[2], yrange[2], interpolate=FALSE)
# add hist with 30% transparency
mh=list()
mh$breaks=seq(x[2], x[length(x)-1],by=step)
mh$mids=sapply(2:length(mh$breaks),function(z)mean(mh$breaks[c(z-1,z)]))
mh$counts=-52.5+12.3*mh$mids-0.804*mh$mids^2+0.0186*mh$mids^3+rnorm(length(mh$mids),0,0.05);mh$counts[c(8,11)]<-mh$counts[c(8,11)]*4/5
mh$equidist= TRUE
class(mh)="histogram"
plot(mh,add=TRUE,col=rainbow(length(mh$counts),alpha=0.3))