Custom icons within 360 panoramas?

I use 360 degree panoramic images in a lot of projects for interactive virtual tours.  And while I'm fine with most of the provided icons, in some cases I could really use the option to import my own icon (png with transparency).

Is there a way to import my own image into the library so I can replace the marker with it?

For instance, I want a client's logo to be the button that needs to be clicked to proceed.  Or, I want my own map marker instead of one of the included ones.

I feel like once the 360 panorama feature was included in Storyline, it doesn't appear to have been updated or enhanced since.