yakindu/plugins/org.yakindu.sct.ui.intro/css/style.css

a#yakindu-documentation-link img,
a#yakindu-examples-link img,
a#yakindu-tutorials-link img,
a#yakindu-user-forum-link img
{
    background-image: url(../img/logo_shadowed.png);
}

a#yakindu-documentation-link:hover img,
a#yakindu-examples-link:hover img,
a#yakindu-tutorials-link:hover img,
a#yakindu-user-forum-link:hover img
{
    background-image: url(../img/logo_hover.png);
}