Transparent area of PNG images in archive rendered black

When my archive images are generated, the transparent area of the PNG image is being rendered black. I’ve already spent a few hours combing through the support threads, and so far none of the suggestions have worked.

I’m using the current version of WordPress with ComicPress. I’ve tried converting my images to 24-bit PNG files and then replacing the old images with the new (suggested by DougJoseph), but it didn’t work.

Is there a plugin or workaround that will give me cleaner looking thumbnail images? It’s fine if the archive thumbnails don’t have transparency – if I can at least make the background white so the footer text is legible, that would be fine.

Any help would be greatly appreciated.

Mike
wickedoffkiltah.com