Hi @jdm,
Here's how to save a ggplot graph to an image file where you specify the image size (and resolution). This also works with SVG format, and graphs from the other R plotting systems (base, lattice).
library(ggplot2)
p1 <- ggplot(data=mtcars, aes(x=disp, y=mpg)) + geom_point() + geom_smooth()
p1
ggsave("my_graph_1.png", plot=p1, height=6, width=8, units=c("cm"), dpi=600)
# PNG format
# 4800 pixels/600 dpi = 8 inches
png(file="my_graph_2.png", res=600, width=4800, height=4800, pointsize=10,
type="windows", antialias="cleartype")
p1
dev.off()
# JPG format
jpeg(file="my_graph_3.jpg", res=600, width=4800, height=4800, pointsize=10,
type="windows", antialias="cleartype")
p1
dev.off()
As image size increases you may need to adjust other graphics elements (e.g. symbol size) to get the result you want.
HTH