This is how you save plots to hard drive when using gglpot. Uisng 300 dpi as resolution should be enough for publication. You have to give the height and width (five is good but use what fits you). You don’t need to scale it down to 0.8.
ggsave("~/gitlab/moralisk.org/p1.png", dpi = 300, scale = 0.8, height = 5, width = 5)