Compare image in picture-box to default image

I assigned Picturebox.Image to Default image. But It still pass the If-statement and open new Diaglog. I don't know why? Please help me!

private void saveBtn_Click(object sender, EventArgs e)
{
    if (imgBox.Image == Properties.Resources.DefaultImage || imgBox.Image == Properties.Resources.EmptyPhoto)
    {
        MessageBox.Show("Warning! Cannot save this image!");
    }
    else
    {
        SaveNoti save = new SaveNoti();
        save.sender = new SaveNoti.SEND(Task_functions);
        save.ShowDialog();
    }
}