Drag the relevant file, which has executable permissions
, to the desktop from a ROX-Filer window that is already open.
Right-click on a desktop icon and select: File 'nameoficon' > Set Icon...
; drag a chosen .png file from a relevant ROX-Filer window, into the box that has opened.
Right-click on any desktop icon, then choose: ROX-Filer > Options > Pinboard
add desktop icons by opening any folder creating icon and dragging onto desktop