brandImage is inlined in Storybook 7

[richardicke]

I updated my Angular SB instance to 7.0.18 (from 6.5.16). I followed the steps in the migration documentation and all is well concerning stories and documentation. However I noticed that the brandImage I set in my theme now gets inlined as base64 where before the update it would be an image resource. The CSP rules on the server where I need to deploy to do not allow this and I would like to set this back to how it was.

SB 6:
<img src="static/media/parachute.b2560560.png" alt="Parachute Design System" class="sto-l8z9zc">

SB 7:
<img src="data:image/png;base64,..." alt="Parachute Design System" class="css-l8z9zc">

I tried tinkering with webpack settings in main.js but this does not seem to have any effect. I would be very happy if someone could point me in the right direction.