From version 3.0 you may select to generate thumbnail from a specific page of the PDF and set it as the featured image. The thumbnail will also be inserted into WordPress' Media Library so you can use it in other post / pages.
For uploading PDFs
Check the box of "Generate featured image from PDF document" and it will show page number dropdown.
If "Delete the old featured image from Media Library" checked, the the old featured image of the PDF will be deleted from WordPress' Media Library after the new thumbnail generated.
For existing PDFs
Please select "Generate Featured Image" from Bulk Actions dropdown and click "Apply" button.
After thumbnail generated
1. The thumbnail will be inserted into WordPress Media Library
You may use the media in other posts / pages.
2. The thumbnail will be set as the document's feature image.
More info: Our plugin use Media id in the WordPress Media Library to save as featured image data so please do not delete the media from Media Library unless you don't need it anymore.Purchase BSK PDF Manager Pro