you could do something like this to get it, but you will have to have skript reflect as a addon to use the java / url stuff!
Code:
import:
java.net.URL
javax.imageio.ImageIO
command skull [<offline player>] [<number>]:
trigger:
SkullChat(arg-1, arg-2)
function SkullChat(p: object, d: number) :: strings:
set {_loc} to new URL("https://minotar.net/avatar/%{_p}%/%{_d}%")
set {_image} to ImageIO.read({_loc})
set {_height} to {_image}.getHeight()
set {_width} to {_image}.getWidth()
set {_size} to {_d}
set {_mult1} to {_height} / {_size}
set {_mult2} to {_width} / {_size}
loop {_size} times:
loop {_size} times:
set {_rgb} to {_image}.getRGB((((loop-value-1) - 1) * {_mult2}), (((loop-value-2) - 1) * {_mult1}))
set {_color} to new (the class "java.awt.Color")({_rgb})
set {_chatcolor} to (the class "net.md_5.bungee.api.ChatColor").of({_color})
set {_image1::%loop-value-2%} to join {_image1::%loop-value-2%}, {_chatcolor}.toString(), "&l⬛"
broadcast {_image1::*}
good luck coding! hope you like this. i t basicly gets the colours and pixels out of the api. use /skull yourname size. to get the skull in chat!
please give me a like if it worked for you!