oh sorry I missed the post one. 
For 30px
.user-card-avatar .avatar-flair, .user-profile-avatar .avatar-flair {
background-size: 60px 60px;
width: 60px;
height: 60px;
}
.topic-avatar .avatar-flair,
.avatar-flair-preview .avatar-flair,
.collapsed-info .user-profile-avatar .avatar-flair,
.user-image .avatar-flair,
.latest-topic-list-item .avatar-flair {
background-size: 30px 30px;
width: 30px;
height: 30px;
}
default 20px
30px
