I didn't think that Bitmaps had alpha channels. Am I incorrect in this? I am using Canopus Procoder to encode some video and it has a "Bitmap Keying" option to add a watermark. But it says that you can enable the alpha channel if your image has one. I am still using Photoshop 6, so maybe my version doesn't support it?
The First is a .BMP that can be saved with a color space of RBG. This file can have an alpha channel.
The second is a file with a color space of Bitmap. The bitmap color space allows for only two colors: 100% Black and white. This file can be saved in many formats. This file cannot include an alpha channel