<img id="imgId" style="position:absolute; left:0; top:0;" src="small_angle.gif" onmouseover="imgOver();" onmouseout="imgOut();" width="30" height="30" alt="" />
<script type="text/javascript">
var animationDelay = 1000;
var animationState = false;
function imgOver() {
    var img = document.getElementById("imgId");
    if (!animationState) {
        animationState = true;
        img.src="big1_angle.gif";
        img.width="200";
        img.height="200";
        setTimeout("animationState = false;", animationDelay);
    } else setTimeout("imgOver()", 100);
}
function imgOut() {
    var img = document.getElementById("imgId");
    if (!animationState) {
        animationState = true;
        img.src="big2_angle.gif";
        setTimeout("animationState = false; imgOutEnd();", animationDelay);
    } else setTimeout("imgOut()", 100);
}
function imgOutEnd(img) {
    var img = document.getElementById('imgId');
    img.src = "small_angle.gif";
    img.width = "30";
    img.height = "30";
}
</script>