[chimerax-users] Error "Cannot determine format for"

Hi! I am trying to get transparent background in png pictures, but it is not working and I get error "Cannot determine format for". Only way to get this is by using command line? I am writing something like: save C:\Users\a\Desktop\k [ format png ] [ supersample 4 ] [ transparentBackground true ] or save C:\Users\a\Desktop\k format png supersample 4 transparentBackground true Also, I have tried different variations. Regards, Mikael