This is a screenshot tool for linux/X11.
I built it by stripping down xannotate's xscreenshot, replacing part of it with farbfeld xscreenshot.
To use it put ff2png (from farbfeld) and screenshot-bin (built using makefile.sh) in $PATH. Then run ./screenshot.
There is a desktop file too which you can drag to your XFCE bar or mkdir -p ~/.local/share/applications/ ; cp Screenshot.desktop ~/.local/share/applications/.