Q: What image format should I use for ebook cover image in my ebook? E.g. PNG, BMP, GIF, JPG, TIFF or TGA?
The best solution for widest device compatibility is to use JPEG (jpg) for photos and PNG for everything else).
Formatting Images Within Your Kindle Book
According to KDP: Kindle Direct Publishing converts images along with text content for upload to the Kindle Store and display on the Kindle and other supported devices. Kindle Direct Publishing can process graphics in the following formats:
- GIF (or .gif)
- PNG (or .png)
- BMP (or .bmp)
- JPEG (or .jpeg)
Remember that Kindle E Ink devices currently have a black and white screen, and images will appear in 16 shades of gray for contrast and clarity. Other Kindle devices and applications, such as the Kindle Fire and Kindle for iPhone or PC, will display images in color.
The Kindle file format internally supports JPEG and GIF images of up to 127KB in size.
An HTML image with an aspect ratio of 9:11 automatically displays with maximum screen coverage.
Kindle Information Source: https://kdp.amazon.com/help?topicId=A1B6GKJ79HC7AN
The Catalog Image
The book cover image that is displayed on Amazon is called the “Catalog Image.” Kindle Direct Publishing accepts two types of files for cover images:
JPEG, or .jpeg
TIFF, or .tif(f)
KDP applies additional compression to images when displaying them on the Amazon website. For best results, images should be uploaded with minimal compression.
Catalog Cover Dimensions
Requirements for the size of your cover art have an ideal height/width ratio of 1.6, this means:
- A minimum of 625 pixels on the shortest side and 1000 pixels on the longest side
- For best quality, your image would be 1563 pixels on the shortest side and 2500 pixels on the longest side
Kindle Catalog Image Information Source: https://kdp.amazon.com/help?topicId=A2J0TRG6OPX0VM
More good information on Images
- Resizing images in Epub by Pigs, Gourds and Wikis: http://www.pigsgourdsandwikis.com/2011/04/resizing-images-in-epub.html
- Image Quality in InDesign by Cari Jansen: http://carijansen.com/2010/09/13/image-quality-and-epub/