Thank you for your quick response, @jeroenooms . It is indeed what I was looking for!
I could do what I was looking for with this code (adapted from yours):
library(magick)
bowser <- image_read('https://upload.wikimedia.org/wikipedia/en/9/92/Bowser_Stock_Art_2021.png') %>% image_scale('200x')
yoshi <- image_read('https://upload.wikimedia.org/wikipedia/en/d/db/Yoshi_%28Nintendo_character%29.png') %>% image_scale('200x')
peach <- image_read('https://upload.wikimedia.org/wikipedia/en/1/16/Princess_Peach_Stock_Art.png') %>% image_scale('200x')
toad <- image_read('https://upload.wikimedia.org/wikipedia/en/d/d1/Toad_3D_Land.png') %>% image_scale('200x')
image_blank(1000, 1000, color = 'white') %>%
image_composite(bowser, gravity = 'north') %>%
image_composite(yoshi, gravity = 'east') %>%
image_composite(peach, gravity = 'south') %>%
image_composite(toad, gravity = 'west')
Now I’ll be investigating how to save that image into a file.
Thanks fro your help!
EDIT: here it is! The magick package: Advanced Image-Processing in R • rOpenSci: magick