Since I found out you can import Adobe Photoshop PSD files directly into Flash all external image updates have been a lot easier. The import function lets you choose options for each layer and you can choose what layers in the file you want to import.

When you want to import layers containing transparency, any objects on the layers behind the transparent portion of the object will be visible through the transparent area. To prevent this, import the transparent layer as “Bitmap image with editable layer styles”.

One feature I would like is that Flash should overwrite the images on the second import. As it is now, you need to copy the library items from the second import to the first manually.