I'm very new to Flash, so please bear with. The Flash file that I've attached plays very slow on my other, older computers. It plays fine on mine, but these older computers play other flash files (i.e adobe.com) fine. I want to know if I'm missing something here as to how making this play efficiently. I understand that I am using photographs - rasterized images - but, is it really supposed to take that much power to play it?
There are a lot of factors that go into optimizing for performance. Bitmaps themselves generally aid in visual performance, but can lead to large load times. Vectors are great for loading quickly but can be a beast for Flash to have to redraw every frame, if they are complex. Filters and blend modes have little to nothing to do with load but can severely hinder performance.
The user’s hardware does come into account as well. If the computer your Flash piece is being viewed on has great amount of RAM, an awesome video card, plenty of hard drive space, etc. then your flash piece will usually play nicely. If the user has a machine with fewer capabilities, your Flash piece will render slower.
Since you are using bitmaps, first thing you will want to do is double click on each one in the library and check its quality settings. If you are using jpgs, they will most likely be at “Use Imported Bitmap quality” which is 102% (weird huh?). Uncheck its radial and enter your own percentage. 75 – 80 is good for quality, less is better for file size. Also, since your jpgs are in constant motion, click the “Allow Smoothing” radial. This will keep your bitmaps from those gross “scan lines” but will be fuzzy if static.
With Vectors, using cacheAsBitmap or turning on the “Use Runtime Bitmap Caching” on the containing movie clip will help performance a little.
To see just what all is taking up loading and how large bitmaps and vectors are, go to your publish settings (File>Publish Settings), in the Flash tab click on "Generate File Size Report." Also, when testing your movie (cntl+enter) hit cntl+B to bring up the Bandwidth Profiler.