How to make a blank PDXObjectImage

[Bryan K Cantwell]

I need to make a 'blank' or just an all white placeholder image for when 
my user fails to upload an image to go in their pdf.
If they upload one I do this:
PDXObjectImage yimage = null;
if (logo.toLowerCase().endsWith(".jpg")) {
    yimage = new PDJpeg(doc, new FileInputStream(logo));
}
How can I just make yimage a blank?

Thanks,
Bryancan