answer:From my basic understanding… I would go for PDF, if only to prevent any unwanted changes made by others. The second reason I’d go for PDF is because text and black/white contrast saves better in PDF than JPG. If you’re more concerned about file size than image quality, then the size of the file depends on the image size and how many pixels are used. If you have a 300dpi photo-ready JPG file, it’s obviously going to be much larger than the internet-standard 72dpi file.