var thumbloopon = new Array();

function loopAnimatedThumb(filename,img,count){
    if(!thumbloopon[filename]){
        img.src = 'thumbs/' + filename + '.jpg';
        return;
    }

     if(!count || count == 0)
         count=4;
    img.src = 'animated_thumbs/' + filename + '_' + count + '.jpg';
    setTimeout(loopAnimatedThumb,1000,filename,img,--count);
}

//var foo = 123; var bar = function () { baz(foo); }; setTimeout(bar, 12345);