The image that appears as an overlay of the target image can be set to transparent, since this is something that we do support. I would suggest you have a look at the png format of your picture and make sure that everything is correct there as this seems to be a format picture issue.
about 3 years ago
I understand that the image to be tracked cannot have transaparent pixels. Can the image that appears as an overlay after the image is tracked have transparent pixels? In my app, the transparent part appears as black.