modify Square theme css width and height in skitter.styles.css inside css folder
it has some default setting for every theme look the first default lines
/* =Square theme
-------------------------------------------------------------- */
.skitter-square .play_pause_button,
.skitter-square .next_button,
.skitter-square .focus_button,
.skitter-square .prev_button
{
display: block;
background: url('../images/sprite-square.png') no-repeat;
}
.skitter-square .play_pause_button {
background-position: -55px -0px;
width: 55px;
height: 55px;
top: 10px !important;
left: 10px !important;
bottom: auto !important;
right: auto !important;
margin-top:0;
}
.skitter-square .play_pause_button.play_button {
background-position: -0px -0px;
width: 55px;
height: 55px;
}