Judging fomr this thread: Luban/CNC dont show transparent image - #6 by Davor it seems that Luban does not handle transparent PNG backgrounds correcty (only inferring, did not test). But embedding the PNG into a SVG seems to do the trick.
Judging fomr this thread: Luban/CNC dont show transparent image - #6 by Davor it seems that Luban does not handle transparent PNG backgrounds correcty (only inferring, did not test). But embedding the PNG into a SVG seems to do the trick.