Take a screenshot of the active window, and open it with a chosen program

The XFCE4 screenshot tool.
More information: <https://docs.xfce.org/apps/xfce4-screenshooter/start>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

xfce4-screenshooter --window --open {{gimp}}

click the source code to copy install xfce4-screenshooter on any operating system with command-not-found.com