FYI, the icon should not be installed into /usr/share/pixmaps but rather /usr/share/icons/hicolor/48x48/apps (or scalable/apps or 24x24/apps, whatever).
FYI, the icon should not be installed into /usr/share/pixmaps but rather /usr/share/ icons/hicolor/ 48x48/apps (or scalable/apps or 24x24/apps, whatever).