Create thumbnail for your existing PDF files.
Thumbnail can be generated from a bitmap (.BMP) or a JPEG (*.JPG) or even a EMF (Encapsulated Meta File).
When thumbnails are created and embedded into your PDF files, you will see the thumbnails displayed on the left column of your PDF Reader or Viewer (usually Adobe Reader).
With this software utility, you can decide whether to show thumbnails when PDF file is opened.