Opening PNG Alpha transparency channel as a mask

[tomczak]

I'm not sure if I'm doing it right: when I open a transparent PNG, the Alpha channel is attached to it as a mask. But when I open this mask in a downstream transformation, the mask seems to be all white.

[jsachs]

I can do this OK here -- is the PNG file 16-bit - I believe 16-bit PNGs can have 16-bit masks, but this should still work OK.

Can you email me the file?

I did find a serious bug with loading a script containing a reference to an alpha channel from a File Open. I have fixed this for the next release.