图片变形了···

 点击游览显示图片 图片要是大 页面就变形了
 本来应该是这样的        <div id="preview_wrapper" class="preview_wrapper">
                            <div id="preview_fake" runat="server" class="preview_fake">
                            <img id="preview_size_fake"  class="preview_size_fake"/>
                            <img id="preview" onload="onPreviewLoad(this)" class="preview" />
                            
                               </div>
                               
                        </div> 这是页面代码
<style type="text/css">
        .preview_wrapper
        {
            display: inline-block;
           
            background-color: #CCCC;
            width: 812px;
            height: 231px;
            text-align:left;
        }
        .preview_fake
        {
            filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale);
            width: 142px;
            height: 248px;
            text-align:left;
        }
        .preview_size_fake
        {
            filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=image);
            visibility: hidden;
            display: inline-table;
            width: 6px;
            height: 194px;
            text-align:left;
            
        }
        .preview
        {
             text-align:left;
            width: 45px;
            height: 87px;
        }
        
        .style3
        {
            width: 183px;
            text-align:left;
        }
        .style7
        { width: 50px;
            text-align: right;
        }
    </style>
    <script type="text/javascript">
        function onUploadImgChange(sender) {
           
            if (!sender.value.match(/.jpg|.gif|.png|.bmp/i)) {
                alert('请上传正常格式的图片');
                return false;
            }            var objPreview = document.getElementById('preview');
            var objPreviewFake = document.getElementById('<%=preview_fake.ClientID %>');
            var objPreviewSizeFake = document.getElementById('preview_size_fake');           
            if (sender.files && sender.files[0]) {
                objPreview.style.display = 'block';
                objPreview.style.width = 'auto';
                objPreview.style.height = 'auto';                objPreview.src = sender.files[0].getAsDataURL();
            } else if (objPreviewFake.filters) {                sender.select();
                var imgSrc = document.selection.createRange().text;                objPreviewFake.filters.item(
            'DXImageTransform.Microsoft.AlphaImageLoader').src = imgSrc;
                objPreviewSizeFake.filters.item(
            'DXImageTransform.Microsoft.AlphaImageLoader').src = imgSrc;                autoSizePreview(objPreviewFake,
            objPreviewSizeFake.offsetWidth, objPreviewSizeFake.offsetHeight);
                objPreview.style.display = 'none';
            }
            document.getElementById("tu").style.display = "block";
        }        function onPreviewLoad(sender) {
            autoSizePreview(sender, sender.offsetWidth, sender.offsetHeight);
        }        function autoSizePreview(objPre, originalWidth, originalHeight) {
            var zoomParam = clacImgZoomParam(300, 300, 440, 330);
            objPre.style.width = zoomParam.width + 'px';
            objPre.style.height = zoomParam.height + 'px';
            objPre.style.marginTop = zoomParam.top + 'px';
            objPre.style.marginLeft = zoomParam.left + 'px';    
        }        function clacImgZoomParam(maxWidth, maxHeight, width, height) {
            var param = { width: width, height: height, top: 0, left: 0 };            if (width > maxWidth || height > maxHeight) {
                rateWidth = width / maxWidth;
                rateHeight = height / maxHeight;                if (rateWidth > rateHeight) {
                    param.width = maxWidth;
                    param.height = height / rateWidth;
                } else {
                    param.width = width / rateHeight;
                    param.height = maxHeight;
                }
            }            param.left = (maxWidth - param.width) / 2;
            param.top = (maxHeight - param.height) / 2;            return param;
        }
        function loadImg() {
            var path = document.getElementById("<%=HiddenField1.ClientID %>").value;
            var imgc = document.getElementById("preview");
            imgc.src = path;
        }
        window.onload = loadImg;        function enlargeImage1() {
           preview.height = "300"
        }
        function dropImage1() {
            preview.height = "150"
        }    </script>  帮帮忙吧·