Note: Following the release of the PDFImport Neo plugin in parallel with DraftSight 2020 SP0, the PDFImport plugin has been retired. For more information concerning the PDFImport Neo plugin, please visit https://www.graebert.com/cad-software/plugins-for-draftsight/
When your images references of the imported PDF-files are not found and only a text note like xyz.jpg is shown in your drawing, this may mean that the image file was moved from the original location prior to the file being generated.
Another scenario on which this may occur is if you are using a DraftSight version prior to V1R4. In following releases, this issue/behavior has been solved, therefore DraftSight version update is recommended.