Child channel icon

[Hectorsky]

Hello , how can I changed child channel icon ,, example I want to change icon just for few of them not all ... Any code ?
Thnks

[Hectorsky]

I found the code :

/* forum icon for forums with old posts (default) */
#forum61 .cell-forum .icon {
    background: transparent url("http://republicamd.com/flags/usd.png") no-repeat;
}
/* forum icon for forums with new posts */
#forum61 .cell-forum .icon {
    background: transparent url("flags/usd.png") no-repeat;
width: 16px; /* icon width */
height: 11px; /* icon height */

But on main page it doesn't show , How can I fix ?