Originally Posted by JSWolf
Isn't that limitation for Mobi and not KF8?
Sort of. The KF8 slice gets scaled down (or for fixed-layout or comic books, recompressed at a lower quality setting) if the image is larger than 256KB.
However, since it's the same tool producing both slices at once, if you want to avoid kindlegen scaling your content, you presumably would have to either use images that are below the smaller limit or include two copies of your image and use @media
rules to use the larger one for the KF8 slice. I have no idea if kindlegen is smart enough to exclude the redundant images or not.
That said, this is all just plain silly. Even 256 KB is absurdly small. In my EPUB version, I'm planning to ship the cover image at just a bit higher resolution than an iPad retina display. At 2040x2640 (JPEG high quality), the smallest
of my three covers is double
the KF8 limit, and the largest is almost four times
the KF8 limit.
The specified size, 256 KB, isn't really even big enough for a full quality JPEG image at Kindle Fire HD resolution, much less iPad retina resolution. Of course, since Amazon doesn't support reflowing KF8 on iPad, iPad users get the 128 KB version. Compared with the 1 MB image, I can actually see the quality difference very easily in certain parts of the image even on a non-retina iPad Mini. I'd expect the difference to be pretty obvious on a full-size, retina-display iPad.
I'll start taking Amazon's KF8 format seriously when they crank that limit up to at least a megabyte, and ideally, two. Until then, my books in KF8 format will always be substandard compared with the EPUB versions, and sadly, there's not a thing I can do about it.