An image widget is fine in the Vuforia Studio Canvas, but in the Preview it displays as transparent static (see attached).
I tried to solve this issue by using a jpg instead of a png, but the issue happened again later to a different image widget that was already a png. So I changed this one to a jpg, and it was fine, but the original image (now a jpg) turned to static. It seems like a glitch in the software - especially since it displays fine in the Canvas & on the Hololens.
sorry for the delay here. I was able to reproduce after letting a preview page sit idle for a while. I'll make sure R&D are aware. Thanks @Wes_Tomer & @AllanThompson for bringing this to our attention.