Method Image.Layer()->alpha()

Method alpha: object set_image(Image.Image image)
object set_image(Image.Image image, Image.Image alpha_channel)
object|int(0..) image()
object|int(0..) alpha()
Description: Set/change/get image and alpha channel for the layer. You could also cancel the channels giving 0 instead of an image object.
Note: image and alpha channel must be of the same size, or canceled.