How to save multiple plots showing raster layers in a matrix grid into a specified folder at 600 resolution as a jpeg in R

I've plotted multiple rasters into a matrix grid and I'd like to save the plot into a specified folder in my directory. My plots are for a poster presentation at a conference and the images need to be really sharp with a resolution of 600.

I know how to save ggplot objects, but I can't figure out how to save this images with this configuration of R code.

When I run my code for the function jpeg, I get this warning message:

Warning message:
In jpeg("Raster_Layers.jpg", quality = 100, units = "px", bg = "white",  :
  NAs introduced by coercion

Code:

#Create an empty raster to plot the rasters
r <- raster(ncols=3, nrows=2, xmn=1, xmx=6, ymn=1, ymx=6)
r1 <- r2 <- r3 <- r4 <- r5 <- r6 <- setValues(r, rnorm(ncell(r)))

#Bind the rasters together in a matrix grid layout of three columns and 2 rows 
m <- rbind(c(1, 2, 3), c(4, 5, 6))
layout(m)

#Select the name the raster layer plot and specifiy to store it in the output folder 
jpeg('Raster_Layers.jpg', 
     quality = 100,
     units = "px",
     bg="white",
     res=600, 
     height=437, 
     width=760,
     file = "/Users/Output")

#Plot the rasters (2 rows by 3 columns) into the grid 
plot(resampled_sss, main = "Mean Sea Surface Salinity (kg/m3)")
plot(resampled_sst, main = "Mean Sea Surface Temperature (°C)")
plot(resampled_chla, main = "Mean Chlorphyll-a (kg/m3)")
plot(depth, main = "Depth (m)")
plot(slope, col=rev(map.pal("viridis",100)), main="Slope (degrees°)")
plot(rugosity, col=rainbow(50), main="Rugosity (degrees°)")
dev.off()

When I try and run my code for the function png, I get this error message

#Create an empty raster to plot the rasters
r <- raster(ncols=3, nrows=2, xmn=1, xmx=6, ymn=1, ymx=6)
r1 <- r2 <- r3 <- r4 <- r5 <- r6 <- setValues(r, rnorm(ncell(r)))

#Bind the rasters together in a grid layout of three columns and 2 rows 
m <- rbind(c(1, 2, 3), c(4, 5, 6))
layout(m)

options(X11.options = c("-dpi", "600"))

#Select the name the raster layer plot and specifiy to store it in the output folder 
png(file = "Raster_Layers.jpg", 
     name.opt = ".X11.Options",
     envir = .X11env,
     quality = 100,
     units = "px",
     bg="white",
     type = "quartz",
     res=600,
     height=437, 
     width=760)

Error Message:

Error: object '.X11env' not found

Screenshot of my Plotted Raster Layers:

Move the layout definition after png device is created, like:

library(raster)
#> Loading required package: sp
r <- raster(ncols=3, nrows=2, xmn=1, xmx=6, ymn=1, ymx=6)
r1 <- r2 <- r3 <- r4 <- r5 <- r6 <- setValues(r, rnorm(ncell(r)))

#Select the name the raster layer plot and specifiy to store it in the output folder 
png(file = '~/Raster_Layers.png', 
     units = "px",
     bg="white",
     res=600, 
     height=3000, 
     width=4000)

layout(matrix(c(1,2,3,4,5,6), 2, 3, byrow=T))

plot(r1)
plot(r2)
plot(r3)
plot(r4)
plot(r5)
plot(r6)
dev.off()
#> png 
#>   2

And the created image:

Or use stack:

png(file = '~/Raster_Layers.png',
     units = "px",
     bg="white",
     res=600,
     height=2000,
     width=4000)

t <- stack(r1, r2, r3, r4, r5, r6)
plot(t, nc = 3, nr = 2)
dev.off()

^{Created on 2024-10-24 with reprex v2.1.0}