I bought an ebook from Aaron Shepard that I followed as a "how to." http://www.amazon.com/Pictures-Kindle-Publishing-Drawings-Formatting-ebook/dp/B00CYPKEN2
He goes over specs and formatting images for fixed layouts and for flowing layouts that have images. It was $1 and took only 30 mins to read. Based on his recommendation, I used Amazon's Kindle Creator program. It is free to download:
It was really easy to use. Once I had my files saved as the specs I wanted, laying out my Children's book took less than 5 minutes. The program creates a .mobi file and it lets you know the delivery size.
I learned from Shepard's ebook that the delivery size is really important, because Amazon charges you per MB to deliver the file when someone purchases your ebook. That is if you are on the 70% royalty plan, which is much more preferable to the 35% plan.
Amazon recommends that you make your files around 300 dpi to protect from future upgrades to software/devices, but that is going to make your file huge and your delivery fees exorbitant. Amazon charges $0.15 per MB. If the file was 25MB, that's $3.75 in fees. I was only planning on selling my ebook for $3.99. So, you either have to go to the 35% royalty scheme, or lower your resolution.
For the ebook, he recommends a 2:3 ratio. I went with 8 in x 6.22 in, which was the same proportions of the files that I had already prepared for print. In testing the files on the ipad and the kindle previewer, there is just a small amount of black bar on the top and bottom. I don't think you can get it perfect, since there are so many different sizes of tablets now. Even though the book says that 75 dpi is fine for devices, I did some tests at different resolutions. 75 dpi was fuzzy, 125 was sharp, and 100 was a little less sharp that the 125. I decided to go with 100dpi, since the sharpness difference was not that much different and it will save on file size. Whatever dpi you choose, when you multiply the pixel length x width, it can't be over 1 million pixels, per Amazon. I set my size to 622w x 800h.
After completing the ebook file through the Kindle Comic Creator, the delivery size came out to under 2 MB! I have 28 pages. So, that means I will only have $0.30 cents in delivery fees for selling on Amazon and will keep 70% royalties of whatever I set the price to.
The whole experience was much easier than I thought. I finished everything in a day, including laying out all the text and resizing the images. The next step will be final proofing and then submitting to Amazon, who will review the file before it can be sold. That means that my book should be up for sale next week!