Fix resize issue with the icon in about widget.
Fix resize issue with the icon in about widget.

shinnok/tarsnap-gui,shinnok/tarsnap-gui,shinnok/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,shinnok/tarsnap-gui,Tarsnap/tarsnap-gui,Tarsnap/tarsnap-gui,shinnok/tarsnap-gui