Icon box Icon above shaded box doesn't style properly with custom image

Hi there,
I have a question about the icon box, the variant (Style) Icon above shaded box. When you choose an existing icon this box looks nice, with the rounded background on top. But when I put my own icon (as an image) in there, the icon appears a lot lower in the box, without the rounded background. How can I get my icon box the same as with an existing icon?
Thanks!
Daphne

Ticket