These resources describe the inners of embeded images in PDF and the way to reduce size of them:
- Ghostscript post about reducing file size.
- Ghostscript documentation. You will find a table describing the main PDFSETTINGS values for screen, ebook and print.
- Short article on command line arguments to reduce PDF file size.
Install ghostcript:
brew install gs
List of details about images in a PDF:
pdfimages -list 1.pdf
