I recently just completed another book with 50 formulas using this method.
Here are a few samples:
I attached a ZIP file with the ODF + PDF + PNG (325dpi if I recall correctly, the client wanted images at a max width of 1000px) versions of the formulas.
The book was called "The Critics of Keynesian Economics" by Henry Hazlitt:
Original PDF:
http://library.mises.org/books/Henry...0Economics.pdf
The final size on 50 of the optimized PNG formulas is 126 KB.