In the version 2.0, we modified the wf_importActivityData to call a different workflow for generating the preview of PDF files. The new workflow, that needs to be imported to existing GN4 system after upgrade, named wf_createPreviewPDF, defines a default preview of 1400px. (GN4-1897).

If you need more pixels or different preview size, modify the wf_createPreviewPDF file and then reload it in the database.