So I just crushed the pngs which brings this down to 80M, but the problem is the mobi format that is produced by kindlegen. I cover the issue here: https://github.com/progit/progit2/issues/116

But basically Amazon produces a file with three files in it - the ePub source, the older mobi7 format and the newer k8 format. This file is meant to be uploaded to Amazon so you can download it from them. Amazon figures out what Kindle you have and sends you the correct version from this file instead of the whole 80M. It's unfortunate, but I'm not sure if I even _can_ take a single format out of the bundle.

If you have a newer Kindle, you should just be able to send the ePub or PDF to it. I'm not sure if it would be a lot worse or not though, I'll try it out.

The images are pretty big, so they'll look good in print and on retina screens. If you run the build locally, you could include a step that ImageMagicks them down to a more reasonable size for a Kindle.

Use the Kindle's "experimental browser" to open the .mobi file from the web somewhere.