Image optimization for Kindle 2
 

The Kindle 2 has 16 levels of gray, so I was wondering if anyone has come up with a decent ICC profile for use in Photoshop to optimize image quality on the Kindle 2. Also, are the previous image resolution specs still the same, i.e., 525x640 in books, 600x800 for screensaver shots? Thanks to anyone who can help.

The images should be stored in color anyway. People who are reading the books on their iPhones get color covers. I assume this is the same for interior illustations?

...I just used the 4-bit grayscale (16-bit) .aco file from this webpage:
http://notlost.blogspot.com/2008/05/...pths-with.html

and then converted the image to indexed color using that palatte. That way you can use photoshop's dithering methods (pattern, noise, etc.) and save a gif/png which is going to be 1:1 exactly what you'll see on the screen.

I excluded interior pictures from my novel because I didn't know what size (as in pixel size) to make them. Does it matter? Will the Kindle fit them to screen? Does anyone know the recommended pixel size for a picture?

Images will be resize to fit the screen and in Kindle 2 the users can click on the image to zoom it. So you should take into account that the resolution of the Kindle 2 screen is (600x800), since the user can click on it to look at the detail, you should preserve your image and the resolution that you want your user to check out.

for example

<img src="Map_Of_US.jpg" width=200 height=300/>

In this way, i can still have paragraph around the images. The user just need to click on the image to see the max resolution of Map_Of_US.jpg. In this case i will include the Map_Of_US.jpg as 600x800, so the users can have fun to zoom it in and look at it.

Have you tried this on the Kindle 2? Conventional MOBI can't effectively wrap text around an image. Or do you mean above and/or below the image? Also, does specifying 200x300 actually give you this size or 400x600 (as it would if the original were 200x300 in size, see Kindle Automatically Doubles Image Sizes)? Note that MOBI only honors width and height if they are shrinking the original image, see Image support.

For images inside a MOBI (AZW) ebook, the largest in-line displayed image size for the Kindle 1 is 525x640 and the Kindle 2 should be similar (images are automatically rescaled to fit). Both now support a 600x800 "zoom" mode, which will also use landscape if necessary, see Kindle now Zooms AZW Images.

Some ebook images were optimized for the Kindle 1 by using only 4 grey scales, and these are now usable but suboptimal on the Kindle 2. If you want to optimize for the Kindle 2, then 16 greyscales and 525x640 or 600x800 or 800x600 are good sizes (keep the original aspect ratio). Note that the Kindle 3 will probably have a screen larger than 600x800 pixels (and the iPhone has a color screen), so device specific optimizations are only a good idea if you really need the very best result on a single device type.

If the original is large and in color, I would use it "as is" in JPEG format. By large I mean at least 500x500, and I would not change the size of images up to about 1500x1500. Let the device rescale the image for you. If the original image is small, then get a larger version if at all possible.

Using hisrc instead of src will make the Kindle2 not trying to upscale it. You are correct that I mean above/below the text. Not the text flow around the the image.

Thanks, Unrequited, that was exactly the kind of guidance I was looking for!

No worries... I've found that "Noise" dithering works best with pictures, but sometimes diffusion looks better overall especially with sharp contrasts.