[e-users] Imlib2

Hi,
Is this the right place to ask about Image::Imlib2 Perl code?
I scan drawings, crop and make the white transparent in Gimp.
I want to blend 2 images like a mix of different images with transparent 
background.
Thought to make them transparent first with
my $new = $image->create_transparent_image(100);
my $new2 = $image2->create_transparent_image(150);
and then blend the two.
The original images loaded into an Imlib image are rgba 0,0,0,0 for the 
transparent areas.
but after saving from Imlib2 the alpha channel has a value like 175.
I don't know anything about the innards of a PNG or how the alpha 
channel works.
If somebody could tell me how to blend 2 transparent images in 
Image::Imlib2 script and retain the 100% transparency that would be 
great.

cheers

mick