ImageButton.xaml

<Button  x:Class="LazyStarter.ImageButton"
             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:LazyStarter"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300"
             Background="Transparent"
             Name="IMGBTN">

    <Button.Template>
        <ControlTemplate>
            <Grid Name="btnGrid">
                <Image Name="contentImage" 
                       Source="{Binding ImageSource, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=local:ImageButton}}"
                       Stretch="Fill">
                </Image>
            </Grid>

            <ControlTemplate.Triggers>
                <MultiDataTrigger>
                    <MultiDataTrigger.Conditions>
                        <Condition Binding="{Binding IsMouseOver, ElementName=contentImage}"
                            Value="True">
                        </Condition>
                        <Condition Binding="{Binding IsImageSourceHoverExist, 
                            RelativeSource={RelativeSource Self}}"
                            Value="True">
                        </Condition>
                    </MultiDataTrigger.Conditions>

                    <Setter TargetName="contentImage" Property="Source" 
                                        Value="{Binding ImageSourceHover,
                                        RelativeSource={RelativeSource Mode=FindAncestor,
                                        AncestorType=local:ImageButton}}"/>
                </MultiDataTrigger>
            </ControlTemplate.Triggers>

        </ControlTemplate>
    </Button.Template>
</Button>