just for fun, the attached file should run the whole gamut of
allocimage chan options in the 32-bit range (with RGB24 thrown in for
good measure) and will create files in /tmp for each possible
combination without involving drawing to the screen display (ideally
this should be done in memdraw, i suppose).

i think page will display them honestly, but i'm not sure. i'll leave
to you to convert the resulting images for outside viewing :)