There is a nice post on Quasimondo that talks about using the Flash 8 BitmapData class as a tool to minimise the file size over head of using external transparent image assets.
To view the full post it can be found Here
I had been considering the uses of the BitmapData class in a related manner. Basically I wanted a method of watermarking external image assets and then removing the watermark when displayed in flash.
The concept i imagined would be to ‘brand’ my images in the Photo Gallery application that i have produced with a specific colour and transparency water mark.
Using the BitmapData class in a similar manner, store an embedded ‘negative’ of the watermark inside the flash movie that would be used to display the images.
Once the external images are loaded the water mark could effectively be removed from the image using the embedded water mark, I assume using a similar ColorMatrixFilter that is being used in the example above.
Alas I haven’t had any time to explore the possibilities of this further……