When you clicked Help>About on Graveman. You will see that the icon used on about dialog was the one used of graveman splash screen. The about dialog was ridiculously big and not suitable for smaller resolution.
This can be fixed by deleting /usr/share/graveman/graveman-main.png
Then replaced it with a symlink to /usr/share/graveman/graveman48.png
rm -f /usr/share/graveman/graveman-main.png
ln -sr /usr/share/graveman/graveman48.png /usr/share/graveman/graveman-main.png
I hope that this hack will include on genpkg_rules of graveman receipt and then repack graveman