Very Noob, quick question on PNG's???

Very Noob, quick question on PNG's???

Hey there, this site is awesome!

I'm very new, programming my first game as a proof of concept and I'm going crazy trying to figure out how to open the PNG files with multiple frames packed into one large file.

I'm doing my first project in AS3 for fun, so anyway to get it into keyframes or multiple images would work with adobe.

Thanks for the help, I've looked everywhere online for this... I'm trying to use one of these: http://opengameart.org/content/animated-particle-effects-2

 

and I'm on a mac

 

T