ClearTest/WpfApp1/pgAuth.xaml

<Page x:Class="WpfApp1.pgAuth"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
      xmlns:local="clr-namespace:WpfApp1"
      mc:Ignorable="d" 
      d:DesignHeight="450" d:DesignWidth="800"
      Title="pgAuth">

    <Grid>
        <StackPanel>
            <TextBox Name="tbLogin"></TextBox>
            <TextBox Name="tbPass"></TextBox>
            <Image Name="imgCaptcha" Width="150px" Height="150px"></Image>
            <Button Content="Войти" Click="Button_Click"></Button>
        </StackPanel>
    </Grid>
</Page>