(url="http://"http://www.ellrx.com/articles/ellsfaq/index.html#transparency"){ eLL's faQ - no.004 : transparency with png and pict formats }(/url)
...Just to clarify the percentages and boundaries of what passes for transparent in the two formats.
As to your specific transparency issue, flash may be indexing your files when saving, negating the alpha channel.
Pop it into PSD and see if under the channels tab (menu->window->show channels) you only have a single channel presumably called 'index'.
if so your alpha channel is negated, indexed png are currently only useful for potentially decreasing image size.
if the image is already small it may increaase size as you have to set up an actual index.
blah blah blah, etc etc..
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looks like i got here a tad too late, any how 24bit png is the same as 32bit png, 32bbit = 24bit( 8bit Red, 8bit Green, 8bit Blue ) + 8bit transparency layer
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... ** Big O..ACTION!**
{ edit : supremme clientele }
(This message has been edited by ellrx (edited 04-09-2004).)