That’s exactly what is happening. Solid background images have a 255 alpha. I even rendered out tgas and a couple of other formats just to double check. As soon as the particle show up, the alpha for the particle works.
To make matters worse when turned off Hardware acceleration and restarted Particle Illusion my recent files show up as gibberish and opening a file OR trying to render a new file results in an error “Encountered an improper argument” I don’t think I’ve ever seen that error when using the the software.
I’ll try updating the drivers and see if that helps.