On Friday I downloaded forms from my superannuation fund to get more money out. These forms are PdFs with pre-filled sections & blank sections. I annotated the PDFs as required & emailed them. On Tuesday a reply email said the sections that were pre-filled & the ones I had completed were blank. So I did it all again, changing one page of seven to a scanned image.
A phone call this morning said that the first two pages were again blank, with page 3 (the scanned one being OK.
This is damned odd behaviour for Apple Mail on the Mac to do.
So I re-annotated pages 1 & 2, printed & scanned them back onto the Mac & added the new pages to the existing PDF after deleting the original first two pages. Then I compressed the PDF with an Automator workflow that's part of the PDF print services. The 7 page PDF went from 8 MB to 2 MB with no perceptible loss of definition: the embedded images were reduced in size/quality.
To be on tne safe side in case Mail decided to play up with the content again I zipped the PDF & attached it & the PDF to the email. Hopefully that will be OK.