Hello Tim, 

You may add this css class

@media screen and (max-width: 460px) {
.bx-def-ava-size{
height:3rem;
width:3rem;
line-height:3rem;
}
}

to modules\aqb\points\template\css\main.css file. It means that avatars become 48px if the screen width less then 460px.