I used PDFs and JPEGs. The files need to be smaller than 6 Mb each. If a PDF isn't, download the full version seven day trial from Adobe. Open each PDF, and using the Save as menu option and save as and optimised PDF. It will drop in size by 70-80%. I scanned everything at 300 ppi. All scans need to be A4. If you scan the front and back of a BRP. for example, put both scans on a singe image and increase the canvas size to A4.