如何隐藏thickbox中的loadinganimation.gif…?

我刚开始使用jquery thickbox。我已经实现了以下代码:

HTML:

<a class="thickbox" href="javascript:void(0);" onclick="javascript:initMap(lat,lng,'htmlmsg',1);" >map</a>

<div id="show_map" style="display:none">
    <div id="map_canvas"></div>
</div>

JS:

function initMap(x,y,msg,flg){
        var map = new GMap2(document.getElementById("map_canvas"),{size: new GSize(400,380)});
        map.removeMapType(G_SATELLITE_MAP);
        map.removeMapType(G_HYBRID_MAP);
        var point = new GLatLng(x, y);
        var htmlMsg = msg;
        map.setCenter(point, 14);
        map.addControl(new GLargeMapControl());
        map.addControl(new GMapTypeControl());
        var baseIcon = new GIcon();
        baseIcon.shadow = "";
        baseIcon.iconSize = new GSize(20, 34);
        baseIcon.shadowSize = new GSize(37, 34);
        baseIcon.iconAnchor = new GPoint(9, 34);
        baseIcon.infoWindowAnchor = new GPoint(9, 2);
        baseIcon.infoShadowAnchor = new GPoint(18, 25);
        var letteredIcon = new GIcon(baseIcon);
        letteredIcon.image = "http://www.google.com/intl/en_ALL/mapfiles/marker.png";
        markerOptions = { icon:letteredIcon };
        var marker = new GMarker(point,markerOptions); 
        GEvent.addListener(marker, "mouseover", function() {    
            map.openInfoWindowHtml(point, htmlMsg);  
        }); 
        map.addOverlay(marker);
        if (flg==1){
            map.openInfoWindowHtml(point, htmlMsg);  
        }
        tb_show('Quick view','#TB_inline?height=400&width=400&inlineId=show_map',true);
    }

问题是“loadinganimation.gif”在thickbox上始终可见,即使在谷歌地图完全加载之后也是如此。