Recently, I created a Pages document that grew to be unusually large in file size due to the images that I was using. The Pages file was roughly 140MB, so even exported to a PDF, it only shrunk to about 50MB—still too big for an email.
Rather than resize the images that I put in the document itself, there’s an easier way.
In Pages, select File > Reduce File Size. This will resize the images according to how large they actually appear in the document itself.
140MB > 1.2MB? Success!