XF 1.3 Is it possible to add icon for custom user fields?

Xenforo 1.3.6

I want to add icons for some of the already created custom user fields like facebook, Skype and etc...
Is it possible and how?

Thank you!
Would it be possible for the member to select a drop-down value expressed in words during registration but show different icons corresponding to those drop-down values in postbit?