images per .xhtml file

galax · 08-16-2024, 04:57 PM

Greetings,

Recently dealing with some images I had doubts how many should be included per page.

What's more convenient, filling the ereader RAM to the max with images in order to reduce internal storage I/O, or fill every .xhtml file with a fewer images?

With these two configurations, what would be a smoother turn page experience?

I am not to familiar with epub image loading and its optimal epub formating.

I'd be glad if anybody can throw some light on this matter.

Thanks in advance.

Quoth · 08-16-2024, 05:31 PM

You don't know what number of pixels wide & high a page is.
You don't know ereader/app ppi.
You don't know physical screen size /ratio
(Media queries only work on some apps and ereaders and platforms).

Epubs that work on any size screen reflow. A new file causes a new page.
Once the page is full, the there is a new page.

The user can change margins, relative line spacing (if there is no line-spacing) and relative font size, so there is no fixed number of pages for two people using the same ereader or same app on same tablet/phone.

Never include line-spacing. It will be automatically suit the font and size, and if not set, the user can change it.

It's only relevant for PDFs and so-called "fixed layout"/"Print replica" to decide on page content in advance, and they need a large screen and are not true ebooks.

Some ereaders will not display if a file is too large.

We test on 4.3" to 10.3" screens for any new kind of content.

Do not be concerned about I/O. In general the more files the better, and a new file starts a new page, so novels at least have a file per chapter. Comics might have a file per layout, so in some cases are one image per file.

galax · Yesterday, 05:13 AM

Rereading my own post I noticed it wasn't very clear to begin with.

What I meant was including images per .xhtml file and not per devices screen size.

Let's say, is it fine for a .xtml file to include hundred

Code:

<img src="../Images/image.png"/>

lines or a thousand?

Or looking at it in another way, let's take the total size of images per .xhtml, is there an established amount of megabytes that should have?

To get an idea as a reference how many megabytes of images does a novel .xhtml chapter have?

Ideally I don't want to exceed nor have too few.

Thank you.

Jellby · Yesterday, 05:29 AM

A reader that's not too dumb should not read all images in memory, it should just read the size in order to do the layout, and read the image only when it's going to be displayed on the screen. So I wouldn't care about it. But if you have thousands of images, maybe for navigation purposes it would be good to have some sections or pagebreaks, and for that you'd split the file. For instance, if I'm doing a compilation of comic strips (one image per day), I'd probably have one file per month.

DNSB · Yesterday, 03:51 PM

At one time, I worked on an ePub that had close to 1000 images per page. An acquaintance was attempting to come close to duplicating an illustrated manuscript so about 50 images for dropcaps and 86 images for normal characters. While the images were relatively small, locating them on the page was a pain. On the computer I using at that time, it took about 4 seconds to display each page. Sadly, they ran out of money before the task was completed.

08-16-2024, 04:57 PM	#1
galax Enthusiast Posts: 26 Karma: 10 Join Date: Sep 2023 Device: none	images per .xhtml file Greetings, Recently dealing with some images I had doubts how many should be included per page. What's more convenient, filling the ereader RAM to the max with images in order to reduce internal storage I/O, or fill every .xhtml file with a fewer images? With these two configurations, what would be a smoother turn page experience? I am not to familiar with epub image loading and its optimal epub formating. I'd be glad if anybody can throw some light on this matter. Thanks in advance.

08-16-2024, 05:31 PM	#2
Quoth the rook, bossing Never. Posts: 12,188 Karma: 89201339 Join Date: Jun 2017 Location: Ireland Device: All 4 Kinds: epub eink, Kindle, android eink, NxtPaper11	You don't know what number of pixels wide & high a page is. You don't know ereader/app ppi. You don't know physical screen size /ratio (Media queries only work on some apps and ereaders and platforms). Epubs that work on any size screen reflow. A new file causes a new page. Once the page is full, the there is a new page. The user can change margins, relative line spacing (if there is no line-spacing) and relative font size, so there is no fixed number of pages for two people using the same ereader or same app on same tablet/phone. Never include line-spacing. It will be automatically suit the font and size, and if not set, the user can change it. It's only relevant for PDFs and so-called "fixed layout"/"Print replica" to decide on page content in advance, and they need a large screen and are not true ebooks. Some ereaders will not display if a file is too large. We test on 4.3" to 10.3" screens for any new kind of content. Do not be concerned about I/O. In general the more files the better, and a new file starts a new page, so novels at least have a file per chapter. Comics might have a file per layout, so in some cases are one image per file. Last edited by Quoth; 08-16-2024 at 05:37 PM.

Yesterday, 05:13 AM	#3
galax Enthusiast Posts: 26 Karma: 10 Join Date: Sep 2023 Device: none	Rereading my own post I noticed it wasn't very clear to begin with. What I meant was including images per .xhtml file and not per devices screen size. Let's say, is it fine for a .xtml file to include hundred Code: <img src="../Images/image.png"/> lines or a thousand? Or looking at it in another way, let's take the total size of images per .xhtml, is there an established amount of megabytes that should have? To get an idea as a reference how many megabytes of images does a novel .xhtml chapter have? Ideally I don't want to exceed nor have too few. Thank you.

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Yesterday, 05:29 AM	#4
Jellby frumious Bandersnatch Posts: 7,525 Karma: 19000001 Join Date: Jan 2008 Location: Spaniard in Sweden Device: Cybook Orizon, Kobo Aura	A reader that's not too dumb should not read all images in memory, it should just read the size in order to do the layout, and read the image only when it's going to be displayed on the screen. So I wouldn't care about it. But if you have thousands of images, maybe for navigation purposes it would be good to have some sections or pagebreaks, and for that you'd split the file. For instance, if I'm doing a compilation of comic strips (one image per day), I'd probably have one file per month.

Yesterday, 03:51 PM	#5
DNSB Bibliophagist Posts: 38,511 Karma: 152905840 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	At one time, I worked on an ePub that had close to 1000 images per page. An acquaintance was attempting to come close to duplicating an illustrated manuscript so about 50 images for dropcaps and 86 images for normal characters. While the images were relatively small, locating them on the page was a pain. On the computer I using at that time, it took about 4 seconds to display each page. Sadly, they ran out of money before the task was completed.

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