Large images on Kindle... what goes on under the hood?

Oxford-eBooks · 11-29-2022, 10:26 AM

A project I'm doing for a client requires relatively large images in the content which they want to be able to zoom in on and examine.
We don't need anything CRAZY, and I'd stick my finger in the air and say 2000px wide would be just fine (with a portrait aspect).

We've got 1000x1692 JPGs in at the moment and if I open up an original image on my PC in the windows image viewer, size the window it to about tablet size and zoom in, it looks kind of okay -- yes, this is not an exact replication, but I get the general feel for how it'll degrade on zoom with THAT partcular zoom algorithm yadda yadda.

The results are less good in KP3 and my last post brought up some really interesting talk about the convesion process when opening in KP3 and also in the final distribution process.

SO:
1. If I put in (say) 2000px wide versions am I going to get 2000 pixels to zoom and pan with on the consumer end?*
2. What processing and rules DOES happen at that point? Image resizing, JPG quality changes, etc. It'll be handy to know what I'm up against next time I have to deal with images that are more than just purely decorative**

Maybe my search-fu is weak, but much of the information I've found is quite old on this, and I KNOW there are certain folk on here that have their ear to the ground re distro processing! :notworthy:

Cheers folks!

===

* On a decent device. Anyone with lower spec of legacy devices are just gonna have to live with it (client is fine with that).

** Yes, yes, all that about critical information should be in live text.

Quoth · 11-29-2022, 10:48 AM

Some older ereader will freeze with a too big image.

You should have at least Kindle App on a smaller screen phone (5") and PW3 or later 6" Kindle and test on those.

About 1/2 of people read Kindle ebooks on a phone.

The Kindle app for iOS may behave differently.

Oxford-eBooks · 11-29-2022, 12:19 PM

Quote:

Originally Posted by Quoth

Some older ereader will freeze with a too big image.

You should have at least Kindle App on a smaller screen phone (5") and PW3 or later 6" Kindle and test on those.

About 1/2 of people read Kindle ebooks on a phone.

The Kindle app for iOS may behave differently.

Although not necessarily the answer to the question I asked, any good advice is always welcome!
From what I've gleaned the absolute maximum image size (or at least for COVERS) is 10,000 sq pixels which is nowhere near where I'd want to go with this.

And also indeed we're checking on KP3 on smaller screens, though that's not related to the queston of how the image gets abused during transit. Not sure I feel comfortable seeing the words "iOS" and "behave" in same Sentence though!

jhowell · 11-29-2022, 08:50 PM

Amazon creates several Kindle e-book formats when a book is published. They also produce multiple variants of each format with different image quality targeted to different app and device types. Image resolution can be reduced and color may be eliminated.

The maximum resolution I have ever seen is around 3500 pixels for comics delivered to the iOS and Android apps. Images delivered to e-ink Kindles max out around 2000 pixels. Perhaps that will change with the new Kindle Scribe.

Customers who use the Download & transfer via USB option can get significantly lower resolution images compared with direct over-the-air delivery of the same book.

11-29-2022, 10:26 AM	#1
Oxford-eBooks Zealot Posts: 127 Karma: 12096 Join Date: May 2010 Device: Loads!	Large images on Kindle... what goes on under the hood? A project I'm doing for a client requires relatively large images in the content which they want to be able to zoom in on and examine. We don't need anything CRAZY, and I'd stick my finger in the air and say 2000px wide would be just fine (with a portrait aspect). We've got 1000x1692 JPGs in at the moment and if I open up an original image on my PC in the windows image viewer, size the window it to about tablet size and zoom in, it looks kind of okay -- yes, this is not an exact replication, but I get the general feel for how it'll degrade on zoom with THAT partcular zoom algorithm yadda yadda. The results are less good in KP3 and my last post brought up some really interesting talk about the convesion process when opening in KP3 and also in the final distribution process. SO: 1. If I put in (say) 2000px wide versions am I going to get 2000 pixels to zoom and pan with on the consumer end?* 2. What processing and rules DOES happen at that point? Image resizing, JPG quality changes, etc. It'll be handy to know what I'm up against next time I have to deal with images that are more than just purely decorative** Maybe my search-fu is weak, but much of the information I've found is quite old on this, and I KNOW there are certain folk on here that have their ear to the ground re distro processing! :notworthy: Cheers folks! === * On a decent device. Anyone with lower spec of legacy devices are just gonna have to live with it (client is fine with that). ** Yes, yes, all that about critical information should be in live text.

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11-29-2022, 10:48 AM	#2
Quoth the rook, bossing Never. Posts: 11,166 Karma: 85874891 Join Date: Jun 2017 Location: Ireland Device: All 4 Kinds: epub eink, Kindle, android eink, NxtPaper11	Some older ereader will freeze with a too big image. You should have at least Kindle App on a smaller screen phone (5") and PW3 or later 6" Kindle and test on those. About 1/2 of people read Kindle ebooks on a phone. The Kindle app for iOS may behave differently.

11-29-2022, 08:50 PM	#4
jhowell Grand Sorcerer Posts: 6,498 Karma: 84420419 Join Date: Nov 2011 Location: Tampa Bay, Florida Device: Kindles	Amazon creates several Kindle e-book formats when a book is published. They also produce multiple variants of each format with different image quality targeted to different app and device types. Image resolution can be reduced and color may be eliminated. The maximum resolution I have ever seen is around 3500 pixels for comics delivered to the iOS and Android apps. Images delivered to e-ink Kindles max out around 2000 pixels. Perhaps that will change with the new Kindle Scribe. Customers who use the Download & transfer via USB option can get significantly lower resolution images compared with direct over-the-air delivery of the same book.