I am using Word 2016 in Windows 10 on this PC.
I have a Word file originally composed elsewhere. I edited it and added three 82mm wide graphics. The "do not compress images in file" is switched off so that images are compressed. The file size is 356KB.


I sent this file to a reviewer who made very minor edits and returned the document. It was 8711KB. It appears to have been edited and saved on a MAC as the reviewer saw the size and zipped the file. The zip file includes a MAC file.
The returned file has the "do not compress images in file" switched on. I switched that off and re-saved. The file size is now 8239KB - still 23 times the original file size.
What more can I switch off on my PC to get it back to the original size?
I have 100 papers to pass to 200 reviewers so this problem may appear again and I don't want to be passing large files around the world.