I have an issue with Draftsight 2020 x64 SP2 (and earlier versions) where an imported (attached) graphic file picture, in my case a .png reference photo, does not have its enabled Transparency property processed (and displayed) correctly at certain zoom levels. It will erroneously display a solid background color (become non transparent) at some zoom levels but yet be correctly transparent at most others. This behavior is most evident when using the mouse scroll wheel to quickly zoom in and out. It always behaves the same (correctly or incorrectly) at the same zoom levels. I have a screen capture video of the problem that I can share with the DS developers. Feel free to contact me for further info.