Tablecells rendered square sized instead of wide when on IE

Hello,
my tablecells are sized as high as it is wide. but i set the cells to be 300px high making. why? can anyone please fix the code? THANKS

<asp:Table ID="Table3" runat="server" Width="100%" CellSpacing="5">
<asp:TableRow runat="server"> <asp:TableCell ID="gallerycel1" runat="server" RowSpan="2" ColumnSpan="2" Width="50%" Height="300px" Style="cursor: pointer; background-image: url(App_Storage/Gallery/1x1.jpg); background-size: cover; height: 300px;"> <asp:ImageButton runat="server" ID="GalleryImageButton1" ImageUrl="~/App_Resources/Images/Theme/Nothing.png" Style="height: 100%; width: 100%; background-image: url(App_Resources/Images/Icons/PlayOverlay.png); background-size: contain; background-repeat: no-repeat; background-position: center;" /> < ...