Converting a layered Photoshop file into pieces you can animate in Flash has traditionally meant exporting each layer as a bitmap, importing each bitmap, making each one into a symbol, cutting and pasting each symbol to its own layer, and rebuilding the layout. For a 20-layer PSD, that approach comes to 171 steps before you even start animating. Illustrator 10 cuts this process down dramatically.
[Of course, if you're serious about animating layered Photoshop artwork, you need to check out LiveMotion 2. It lets you drag in a PSD, convert layers and layer sets to objects, groups, or sequences, and even re-edit the whole PSD in Photoshop & automatically update the artwork inside LiveMotion. You can then integrate SWFs made with LiveMotion into your Flash SWFs using Load Movie. But back to the story at hand...]
- When you choose File->Open and point Illustrator at a PSD file, it will offer to flatten the image or to convert each layer to an Illustrator layer. Choose to convert layers to AI layers.
- Once each Photoshop layer is on its own Illustrator layer, you can treat it as you would any other placed image (make it into a symbol, scale or rotate it, combine it with vector artwork etc.).
- Choose File->Export, pick SWF from the format menu, and tell Illustrator to export AI layers as SWF frames or as separate SWFs. Unless I'm using symbols in this case, I find it easier to export layers as separate SWFs & avoid the task of moving each one to its own layer inside Flash.
- Pick a bitmap format. Illustrator will export bitmaps as PNG files in SWF & preserve their 8-bit transparency data. Since you can choose per-object compression in the export dialog box, I generally use Lossless compression, then optimize each bitmap inside the Flash library.
- Hit OK and import the SWF or SWFs into Flash.