The maximum of transparent clips you can have in a Flash movie is tricky. I imported a bunch of PNG files, and found that after the first couple dozen, the transparent portions of my images were not, in fact, transparent. Why? And how to fix it?
Well, transparent PNGs, layered atop one another, only have as many transparent spots available as they have bits. A 24-bit PNG? 24 transparent images. 32-bit PNG? 32 transparent images.
There are two resolutions I’ve heard of, though I haven’t had a chance to try them yet: one is check the Cache as Bitmap checkbox. The other is to Break Apart your image, select the transparent chunk(s), and delete them. Then convert your image to a movieclip (or symbol) and you should be able to start layering them just fine.
I post this because it took me FOREVER to Google a solution, so I wanted a findable answer to the question “Why are my transparent images not transparent in Flash?” It has been an issue for me in AS3 and AS2, so Flash 8, 9, 10, whatever, all have the same problem and solution.
If this helps you, please follow me on Twitter! It’s the best thanks a fella could get.