append 2 images and set margin/positions

[antoine4ucsd]

Hello
I am trying to combine 2 plots but I need to adjust the position of the bottom plot to be aligned with position 1 of the x axis of the top plot. I am trying the following (among many other attempts...):

bottom_image<- image_border(image_background(bottom_image_raw, "white"), "white", geometry = "500x10")
final_plot <- image_append(image_scale(c(topimage,bottom_image), "1200"), stack = TRUE)

but as you can see on the attached output, the bottom image is too far on the left. the 5'LTR box needs to start at pos 1 of the above figure. how can I adjust the postion of the bottom figure only (or add a left border first?)

if there is a better to combine those files (raster/ggplot), I am eager to learn alternative options.

thank you!