Please Note: 
1. The image has to be in 600 DPI resolution.
2. Image Height="3510" has to be in this range to reproduce the issue.
            <Image Source="htl.tif" Height="3510" Stretch="Uniform" StretchDirection="Both"/>
This is my test code as follows:
XAML
<Window x:Class="WpfApplication1.ScrollViewImage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="ScrollViewImage" Height="300" Width="300">
    <Grid>
        <ScrollViewer Margin="5" HorizontalScrollBarVisibility="Visible" VerticalScrollBarVisibility="Visible">
            <Image Source="htl.tif" Height="3510" Stretch="Uniform" StretchDirection="Both"/>
        </ScrollViewer>
    </Grid>
</Window>
Regards,
M.Mohamed Anwar