<form id="frmForm" runat="server">

<asp:ImageButton runat="server" ID="btnIt" src="img/it.png" OnClick="btnIt_Click" CausesValidation="false" />
<asp:ImageButton runat="server" ID="btnEn" src="img/en.png" OnClick="btnEn_Click" CausesValidation="false" />

<label for="login" class="label1">Login</label>
<asp:TextBox runat="server" ID="txtLogin" CssClass="txt1"></asp:TextBox>
<label for="login" class="label2">Password</label>
<asp:TextBox runat="server" ID="txtPassword" TextMode="Password" CssClass="txt2"></asp:TextBox>
<asp:Button runat="server" ID="btnLogin" CssClass="btnsub" CausesValidation="true" />

</form>