JPG ImageBrush ImageSource值不在预期范围内

Question

I have been srtuggling on this one for quite some time, looking everywhere I could on SO and Google without success.
I want to display a background image in some simple window (How Ambitious!)

<Window x:Class="HelloWorld_Lite.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        WindowStyle="None" ResizeMode="NoResize"
        Title="Hello World" Height="350" Width="525">
    <Window.Background >
        <ImageBrush ImageSource="HelloWorld-Lite;component/Background.jpg" />
    </Window.Background>
    <Grid>
    <Label Content="Hello World!" Height="28" HorizontalAlignment="Left" Margin="225,30,0,0" Name="label2" VerticalAlignment="Top" />
    </Grid>
</Window>

The image has been added to the project (Add > Existing Item) and is built as "Resource"
I did a clean up and rebuild, but this thing is still trying my nerves.

Please Tell Me I missed something obvious

Edit : Saving the file to PNG format fixed the problem(?). PNG size = 2Mb, JPG size=360k.
If this is a limitation, this is just ridiculous.

Edit 2 : Resizing the original JPG from 1280x853 to 480x320 also fixed the problem.
Hence, It looks like a size limitation specific to JPG format.

Answer 1

As per the iterative process above, two fixes are possible

1) Preserve file size by converting the image to PNG format
2) Preserve JPG format by reducing image size