Hey again.
This is done through CSS with a font:
.fa-facebook-square:before {
content: "\f082";
}
.fa-twitter-square:before {
content: "\f081";
}
.fa-google-plus-square:before {
content: "\f0d4";
}
.fa-rss-square:before {
content: "\f143";
}
They use FontAwesome:
https://fortawesome.github.io/Font-Awesome/icons/
You could either change the colour, Look at their options or you could do your own thing like:
.fa-rss-square:before {
content: url(IMAGEURL);
}
Replace IMAGEURL with a url. Or you could look at doing your own font thing:
https://www.dafont.com/search.php?q=social
Hope that helps.
Take care.