I am attempting to export a PNG image file from ArcGIS Pro 1.2.0 with the background set to transparent. In ArcMap 10.3 this is simple, there was a button for setting the transparent color to white during the export.
The goal is just to find similar settings to the screenshot above. For this project, I have a basemap as a standalone PDF file. I need to overlay a callout box over top of that file--this requires that the callout box has transparancy all around it, and not a white box (like what happens when you clip to extent).