You may get this error when generating your PDF catalog:
Erreur 'TCPDF ERROR': [Image] Unable to get image
This means that either an image associated to a product or a category included in the catalog is invalid, or permissions on the folder where the images are stored, at the root of your shop /img/p/ are insufficient.
You can refer to this article to help you increase the permissions via your FTP.
For more information on the PDF Catalog Module, please refer to our online documentation.