scuttle-firefox/chrome/scuttle/skin/classic/scuttle.css

/* My Scuttle */

#scuttle-button-my {
    list-style-image: url("chrome://scuttle/skin/scuttle-button-my.png"); 
    -moz-image-region: rect(0px 24px 24px 0px);  
}
#scuttle-button-my:hover {
    -moz-image-region: rect(24px 24px 48px 0px);
}
#scuttle-button-my[disabled="true"] {
    -moz-image-region: rect(48px 24px 72px 0px) !important;
}

toolbar[iconsize="small"] #scuttle-button-my {
    list-style-image: url("chrome://scuttle/skin/scuttle-button-my-small.png");
    -moz-image-region: rect(0px 16px 16px 0px);
}
toolbar[iconsize="small"] #scuttle-button-my:hover {
    -moz-image-region: rect(16px 16px 32px 0px);
}
toolbar[iconsize="small"] #scuttle-button-my[disabled="true"] {
    -moz-image-region: rect(32px 16px 48px 0px) !important;
}

/* Scuttle This Page... */

#scuttle-button-add {
    list-style-image: url("chrome://scuttle/skin/scuttle-button-add.png"); 
    -moz-image-region: rect(0px 24px 24px 0px);  
}
#scuttle-button-add:hover {
    -moz-image-region: rect(24px 24px 48px 0px);
}
#scuttle-button-add[disabled="true"] {
    -moz-image-region: rect(48px 24px 72px 0px) !important;
}

/* Scuttle All Pages... */

#scuttle-button-multiadd {
    list-style-image: url("chrome://scuttle/skin/scuttle-button-add.png"); 
    -moz-image-region: rect(0px 24px 24px 0px);  
}
#scuttle-button-multiadd:hover {
    -moz-image-region: rect(24px 24px 48px 0px);
}
#scuttle-button-multiadd[disabled="true"] {
    -moz-image-region: rect(48px 24px 72px 0px) !important;
}

toolbar[iconsize="small"] #scuttle-button-add {
    list-style-image: url("chrome://scuttle/skin/scuttle-button-add-small.png");
    -moz-image-region: rect(0px 16px 16px 0px);
}
toolbar[iconsize="small"] #scuttle-button-add:hover {
    -moz-image-region: rect(16px 16px 32px 0px);
}
toolbar[iconsize="small"] #scuttle-button-add[disabled="true"] {
    -moz-image-region: rect(32px 16px 48px 0px) !important;
}