How Do I Change Css Height Using Jquery, And Fixed It, When There's An Image

#chartPreview
        {
            position:fixed;
        }.imgPreview
        {
            display:none;   
        }

$j(document).ready(function ($) {
                $j('#delete').hide();
                $j('#upload').click(function ($) {
                    $j('#<%= fuFiles.ClientID%>').click();
                });
                $j('#delete').click(function ($) {
                    $j('#imgPreview').hide();
                    $j('#upload').show();
                    $j('#<%= fuFiles.ClientID%>').attr('value', '');
                    $j('#delete').hide();
                    $j('#<%= btnImageSend.ClientID %>').hide();                    
                    $j('#btnSave').show();
                    $j('#<%= txtShout.ClientID %>').css('height','30');

                });
            });

            function readURL(input) {
                if (input.files && input.files[0]) {
                    var reader = new FileReader();
                    reader.onload = function (e) {
                        $j('#imgPreview').show();
                        $j('#upload').hide();
                        $j('#chartPreview').attr('src', e.target.result);
                        $j('#delete').show();
                        $j('#<%= txtShout.ClientID %>').css('height', '90');
                        $j('#<%= btnImageSend.ClientID %>').show();
                        $j('#btnSave').hide();
                    }
                    reader.readAsDataURL(input.files[0]);
                }
            }

            $j(document).ready(function ($) {
                $j("#<%= fuFiles.ClientID %>").change(function ($) {
                    readURL(this);
                    document.getElementById("<%= hdnFile.ClientID %>").value = "N";
                    $j('#<%= txtShout.ClientID %>').css('height', '90');
                });
            });

<div id="imgPreview" class="imgPreview">
                                          <%--<table style="width:100%; text-align:center;">
                                              <tr>
                                                  <td align="center" style="width:100%">
                                                      <div class="chartPreview1" id="chartPreview1">--%>
                                                          <img class="chartPreview" id="chartPreview" alt="chartYours" src="#" height="80" width="80" />
                                                          <a href="#"><img id="delete" alt="deleteImage" src="../images/deletestockpick.png" height="20" width="20" style="position:absolute; margin-top:0px;margin-left:60px;"></img></a>
                                                      <%--</div>
                                                  </td>
                                              </tr>
                                          </table>
                                      </div>--%>