I had the same problem and, after some experimenting, I found what seams to be another Bryce's bug: When you load your pic by clicking at the top of the first pic and copy&paste to the 2nd chanel, the alpha chanel information losts contrast. You end up with that semi-transparent pic you mentioned. If you load the same pic by clicking at one of the empty pic buttons below it works allright. Funny, isn't it?