Some websites set a background image to advertise, e.g.
<body style="background-image:url('images/adv.png')">
I'm wondering how I can write an AdBlock Plus filter in order to hide the <body> background.
Turns out there's no way to hide a background without hiding the whole element — but you can always block the single image by adding a custom ABP filter.
You can do so by pressing CTRL + Shift + V (open blockable items), and look for the image you want to hide.