I think you mean this part of the CSS file:
/* $BOARDICONS */
/* ------------------------------------------------------- */
.board_icon {
display: block;
float: left;
width: 48px;
height: 48px;
}
.board_key:before {
display: block;
float: left;
height: 24px;
width: 26px;
content: "";
}
.category_boards .board_icon, .board_key:before {
background-repeat: no-repeat;
background-image: url(../../images/_light/board_icons.png);
}
.on_board {
background-position: 0 0;
}
.on2_board {
background-position: -72px 0;
}
.off_board {
background-position: -144px 0;
}
.redirect_board {
background-position: -216px 0;
}
.new_some_board:before {
background-position: -300px -14px;
}
.new_none_board:before {
background-position: -372px -14px;
}
.new_redirect_board:before {
background-position: -444px -14px;
}
So the solution can be to tell the forum that it has to use single images for on, on2, off, and the new stuff. For example:
.on_board {
background-image: url(../../images/_light/board_icon_on.png);
}
Not tested.
But what needs to be done with:
.category_boards .board_icon, .board_key:before {
background-repeat: no-repeat;
background-image: url(../../images/_light/board_icons.png);
}