But I had to figure out a few things that I'm sharing now in the hope of helping other folks.
Note: This approach is for creating a very basic ebook. It won't have a table of contents that people can use to navigate within it. For ebooks consisting primarily of text, a functioning table of contents is customary, but picture books and comic books are designed to be read without interruption, and all ebook software remembers the last page someone was on, so I suspect few readers will notice.
- A program to resize your pages and save them as jpegs.
- A program to save those jpegs as a pdf file.
- A program to turn the pdf files into an epub file.
What you need to know about page size and file size
Page size refers to the number of pixels in an image. File size refers to the number of bytes needed to store it. Keep both in mind when you're making your book.
Because there are so many tablets available, you have many possible choices about page size. I chose a width of 600 pixels, which means most ebook readers will display them at actual size. (The length of my pages varied, but most were at or near 900 pixels.)
If you want people to be able to zoom in for more detail, choose a larger page size, but remember the 127 KB limit for the page's file size. Be prepared to save your files as medium or low quality jpegs.
Amazon will let you sell ebooks as large at 50 megabytes, but Barnes & Noble's limit is 20 MB. You could choose to only sell on Amazon, but you'll reach more buyers if you sell on Barnes & Noble too. Keep your total file size under 20 meg, and you can sell your book on both.
How to make a basic picture-based ebook
1. Resize your pages.
2. Assemble them in an epub file smaller than 20 MB.
3. Go to Kindle Direct Publishing to make your Amazon book. There's one tricky thing: KDP offers two royalty options, one that gives you 35% of the cover price or one that gives you 70%. If you choose the 70% plan, you have to pay 15 cents a meg for each download, which makes large files incredibly expensive. Choose the 35% plan for free distribution.
4. Go to Pubit to make your Barnes & Noble book. Probably because they don't allow files larger than 20 MB, they don't offer royalty choices: there's no charge for downloads, and you get 65% of the cover price.
A note about pricing: You might be tempted to charge more for the Amazon book because Amazon takes a bigger cut. Don't. Amazon will notice if your book is cheaper elsewhere and reduce its price automatically to match it. Just accept that you'll get a different rate for Kindle sales than for other readers.
Update 1: On Google +, Stephen Geigen-Miller asked, "Have you gotten any feedback about the image quality? I've heard that graphics files need to be optimized differently for ebooks."
I answered, "Alas, no feedback yet. I was working with old files, so I decided not to spend time optimizing them, but if I was doing new work, I would try to find the magic spot between file size and image quality."
Update 2: Steven Sudit added, "I read them on my wife's Kindle Fire, and it was fine."
Update 3: Thanks to IRS requirements, selling comics this way is harder if you aren't a US citizen. See: Comics in the New Media ~ Part III
Update 4: Amazon Kindle Tax Information for Non-US Publishers.