How can I remove black background from a image widget

Hi there,
can somebody fill me in, how I can remove the black background from widget-image?
I have this dashboard which fits a 7" kindle:

This is the code I have in place to load the image from my camera:

<div class="section" style="max-width:960px">
 <div  ng-init="image={url: '', refresh: 5}" style="background-color: transparent">
<widget-image ng-model="image" style="background-color: transparent"></widget-image>

Obvioulsy the “style” portion is not working. Already tried ng-style as well.
Goal is to show only the greenish section background.
Base code is taken from the matrix-theme by pmpkkPatrick and adapted with code from Michael_Stjerna

I kind of fixed it by adding the item box-content to the css file using !important tags with the background color as black was already in the “inline css”.

Wonder if that is the correct approach here