import utility comes preinstalled with ImageMagick
with selection
import test.png
for specific window
import -window "$(xdotool getwindowfocus)" test.png
for all monitor
import -window root test.png
for croping specific monitor or resolution
import -window root -crop 1920x1880+0+0 test.png
for gravity option
import -window root -gravity NorthEast -crop 1920x1080+1920+8 test.png
for more than one screenshot
import -snaps 3 test.png
for with delay
sleep 3 && import test.png
adding effects
negating colors
import -negate test.png
- monochrome
resizing image
import -resize 25% test.png
rotate image
import -rotate 45 test.png
setting transparency for colors
import -transparent '#33393B' filemanager.png