Extract alpha from PNG

Is there a way to extract the alpha channel from a transparent png file?
I would like to use the 8 bit grayscale of that png.

In the picture object the mask is nil. So, it is not stored there… where is it? :confused:

if you load it in xojo, you can check if it has a mask and use the mask.

(or first convert it into a picture with mask)

or if you need bytes use PictureReaderMBS class.