[magick-users] PNGs with palettes and multibit alpha channels

[Sam Kerner]

Hello,
    I have some PNGs which do not use a palette and have
semi-transparent pixels.  Each image has fewer than 256 unique colors.
 To reduce the size of these files, I would like to convert them to
PNGs with a palette.  When I use 'convert in.png png8:out.png',
out.png has a one-bit alpha channel, so the semitransparent pixels are
no longer semi-transparent.  I also tried '-type palette' and '-colors
256', without success.
    Can a PNG use a palette and have semi-transparent pixels?  If so,
how do I create one with imagemagick?

Sam