I've been exporting a couple of display stand artwork pieces from inDesign cc19. My background flattened jpeg in the inDesign document is 200dp and the rest is a few vector objectsi. I export using the PDFX1a:2001 spec as this is what the printer requested. By default the file size for 1.07GB, which is huge. I adjusted the downsampling on export and found that setting it 143dpi produces a 15.3MB PDF, yet changing it 144dpi makes the file hundreds of MBs. So 1 dpi changes drastically how big the PDF output file size is. Why is this?