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I would like to embed images into my ebook, but I could not find any general references that describe "best practices" related to image format, size and resolution.

Are there any standardized or recommended guidelines or references that describe what file format (Jpeg, PNG, BMP, etc.), what size (minimum/maximum Width and/or Height), and what resolution (minimum/maximum DPI) would be able to be handled by most ebook readers? I am thinking along the lines of "agreed industry standards", if any…

  • You should probably make the SVG part into a separate question. – Anthon Dec 19 '13 at 6:31
  • @Anthon OK, thanks for the tip. [ link ] I guess a beta can't have enough questions, can it? ;) – e-sushi Dec 19 '13 at 6:34
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    That, and it more easy to answer, and fair to people knowing the answer to only one of the questions (being able to get their (partial) answer accepted, voted upon). – Anthon Dec 19 '13 at 6:36
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The short answer is no, and I don't expect there to be anything like that with a single recommendation.

The reason is that different input material is better rendered in different image file formats. All material handles well in non-lossy formats (among others most of the TIFF formats, PNG), however such format produce large files. When you look at space saving compressed formats, photos handle well in JPEG, and images of scanned text are best represented in DjVu.

My own experience from scanning mangas drawn on paper (so my daughter can take them on her ebook) are that for that, JPEG is a good format and that I best convert the scan to the physical dimensions of her reader. This gives optimal size of the files. And because of the interpolation that is done on the computer vs the one on the device is of better quality, it looks better and is faster in displaying. I noticed this when I had generated her drawings in EPUB form for my reader (with a higher resolution) and then read the same EPUB on hers. The images are combined in a simple EPUB file with the stylesheets setting borders to 0. (I do all calculations for that in pixels, not bothering with physical sizes and resolution, which in the end resolves to the same).

  • what about size - I've found it esp. challenging to control the size of the image as it seems different devices have different ways they prefer to control size. In iBooks for example, I have found it's better to control the size of the div holding the image than trying to write CSS rules for the .img class itself. – maxwell Dec 12 '14 at 19:20
  • @maxwell I generate the size of the image to the specs of what the target device can handle. Further "scaling" using CSS in any form is then not necessary. That gives the best result – Anthon Dec 12 '14 at 22:27

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