button按下后，背景变成纯色了。
我想要平常是“图1”，按下后变成“图2”，问下怎么设置？！

希望能有个稍微详细的说明。

详细说明不好说啊，这个就是改模板，生成默认模板需要用到Blend来做一个副本。

<Button Content="登录" HorizontalAlignment="Stretch" Margin="10,46,10,0" VerticalAlignment="Top" Grid.Row="3" Height="86" FontSize="24" BorderThickness="0" Foreground="White" Padding="0" Click="login_Click">
            <Button.Resources>
                <Style x:Key="ButtonStyle1" TargetType="Button">
                    <Setter Property="Background" Value="Transparent"/>
                    <Setter Property="BorderBrush" Value="{StaticResource PhoneForegroundBrush}"/>
                    <Setter Property="Foreground" Value="{StaticResource PhoneForegroundBrush}"/>
                    <Setter Property="BorderThickness" Value="{StaticResource PhoneBorderThickness}"/>
                    <Setter Property="FontFamily" Value="{StaticResource PhoneFontFamilySemiBold}"/>
                    <Setter Property="FontSize" Value="{StaticResource PhoneFontSizeMedium}"/>
                    <Setter Property="Padding" Value="10,5,10,6"/>
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="Button">
                                <Grid Background="Transparent">
                                    <VisualStateManager.VisualStateGroups>
                                        <VisualStateGroup x:Name="CommonStates">
                                            <VisualState x:Name="Normal"/>
                                            <VisualState x:Name="MouseOver"/>
                                            <VisualState x:Name="Pressed">
                                                <Storyboard>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneButtonBasePressedForegroundBrush}"/>
                                                    </ObjectAnimationUsingKeyFrames>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneAccentBrush}"/>
                                                    </ObjectAnimationUsingKeyFrames>
                                                </Storyboard>
                                            </VisualState>
                                            <VisualState x:Name="Disabled">
                                                <Storyboard>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentContainer">
                                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                                    </ObjectAnimationUsingKeyFrames>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonBackground">
                                                        <DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource PhoneDisabledBrush}"/>
                                                    </ObjectAnimationUsingKeyFrames>
                                                    <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonBackground">
                                                        <DiscreteObjectKeyFrame KeyTime="0" Value="Transparent"/>
                                                    </ObjectAnimationUsingKeyFrames>
                                                </Storyboard>
                                            </VisualState>
                                        </VisualStateGroup>
                                    </VisualStateManager.VisualStateGroups>
                                    <Border x:Name="ButtonBackground" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="0" Margin="{StaticResource PhoneTouchTargetOverhang}">
                                        <ContentControl x:Name="ContentContainer" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Foreground="{TemplateBinding Foreground}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"/>
                                    </Border>
                                </Grid>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </Button.Resources>
            <Button.Style>
                <StaticResource ResourceKey="ButtonStyle1"/>
            </Button.Style>
            <Button.Background>
                <ImageBrush Stretch="Fill" ImageSource="Assets/Chery/login/button3_a.png"/>
            </Button.Background>
        </Button>

visualState，给你一个简便的方法，可以尝试使用blend，blend编辑中，visualState很方便。