In order for PDFs to be displayed correctly in the Kiosk App, you should check your PDFs for the following properties:
Each separator line, table border and chart is an element described as vectors in the PDF, also characters are represented as vectors. They are not specified image files. Our Image Extractor searches the PDF for embedded image files, extracts them and determines their coordinates on the PDF pages. If an image is to be converted, the image file must be present in the PDF.
Vector graphics in the PDF are not embedded images. If you want to have graphics as image widgets, you must save these graphics as raster graphics on the page (as JPG or PNG) when creating the PDF.