What is the best (performance) way to animate 55 png images in Adobe Flash?

We are using Adobe Flash to produce software for an interactive touch screen kiosk. I have 55 1024x768 24 bit开发者_如何学C PNG images. I want to play them (fairly regularly...once every 5 minutes or so) without them stuttering but can't find a good dependable way, main problem is I think Flash GC's them after an arbitrary idle period. Reason I'm doing this is because the FLV attempts we have made aren't sufficiently high quality. I also looked at using a H.264 but that obscures any other assets placed over it. I have a number of text fields sitting over this animation.

The machine in question is a Core2 Duo, 4GB Ram, GeForce 9500GT.

Any ideas would be appreciated!

Personally, I'd do an FLV.

Here is what I did:

1. Created a new project: 1024 x 768
2. Created the order of the pics in the timeline in separate frame.
3. Exported using QuickTime H.264
4. Converted to the FLV listed above.