Earlier quoted context omitted.
User: How do I fix large pdf files? ChatGPT: delete system32
Had to finally register there to check. This was the answer. "There are a few things you can try to fix large PDF files: Compress the PDF: You can use online or offline tools to compress the PDF file. This will reduce the file size and make it easier to work with. Some popular tools for compressing PDFs include Adobe Acrobat, Smallpdf, and PDF Compressor. Remove unnecessary elements: If the PDF file contains images,…
It isn't very helpful, though.
Adobe has a method of compressing pdf files that is quite effective while retaining the quality of images, etc, e.g. 50 MB to 3 MB, so you can now email it. However you can only use the free version a few times before it wants all your data as well as the data of your first born. I'm too stingy to pay Adobe...
I haven't (yet) found free pdf compression that doesn't mangle images... (would be glad to try any that HN might suggest!).