Request policy plugin doesn't capture background image requests ?

Hello all,

I'm using FF v52 with the "RequestPolicy" 0.5.28.1 plugin. Which works
great.

Though while visiting a website[1] I discovered that the plugin doesn't
block images that are loaded as backgrounds.

[1]https://www.tp-link.com/nl/business-networking/ceiling-mount-ap/eap225/

In specifically, stuff like this :

div class="tp-home-case-item-box"
style="background-image:url('https://static.tp-link.com/Transportation_01_Russian_Railway_1597730093010u.j pg')"


tl;dr:
Does anyone recognise this and knows if there is a newer plugin that doesn't
have this ... bug(?), or even just a fix for it ?

Regards,
Rudy Wieser