[CentOS] Question on /usr/bin/import for CentOS 7

Fri Jan 13 20:18:42 UTC 2017
Jerry Geis <jerry.geis at gmail.com>

Ok - I thought maybe the beep was due to error - but apparently not.
I have found how to disable the beep with the -silent option

However - I am still not able to get a screen shot - it resulting png is
just black or black.
export DISPLAY=:0.0
import -silent -window root screen.png

the file is just all black.