load & unload movie in the same button

Hi. i'm loading a jpg into a holder with a button. but would like the same button to unload the mc...
something like

on release
if holder.loaded
unload
else
load....

thank you in advance

loadMovie automatically performs unloadMovie to clear the holder clip

test with a fast setInterval (1) and trace the bytesTotal property,
for a split second it will show 0 as the unloadMovie action is activated

i'm sorry i didn't understand..
can anyone explain me, please

if loading into same holder, no need to unload, it does it automatically

any clearer .. ?? :)