Besides file size, is there any reason I shouldn't use images larger than 600px wide

[SarahMB]

I am new to e-publishing, so please forgive me if this is a silly question. I have tested this out by using images at, for example, 1000 px wide. When previewed in the online Kindle previewer, they seem to automatically size down to auto width or height (which ever hits the page margin first). It keeps proportion and seems to look fine. What is the down side to using images larger than the screen? If my file size is below the max file size, then should I still be concerned about optimizing the photos?

Thanks for your help!

Sarah

[AnemicOak]

Most outlets have requirements or recommendations for minimum cover sizes...

Apple = at least 1,400 pixels wide required
Amazon = 625x1000 minimum, 1563x2500 recommended
B&N = 1,200 to 2,000 pixels high recommended
Smashwords = Same as Apple

With all the higher resolution devices it's nice to have high rez covers (speaking as a consumer). The biggest thing for an author/publisher to keep in mind is that higher rez is nice, but some distributors (such as Amazon) charge a fee based on the size of your file.

This post on cover size from Smashwords might be helpful..
http://blog.smashwords.com/2012/06/n...uirements.html

[PeterT]

I think Sarah is asking about images in general; not just covers.

[AnemicOak]

Originally Posted by PeterT

I think Sarah is asking about images in general; not just covers.

I guess I missed that. Still I'd think you'd want to take into account people using higher rez screens. I know it sucks when I get a book that has a map or two and the publisher includes small images.

[Jellby]

Large images are scaled down, fine, but this means two things:

1. The device must do the downscaling itself, this could make everything slower if there are many images.

2. The downscaling algorithm used by the device typically gives noticeably worse results than what you can get with an image processing program.

But, of course, there are also reasons to use large images

[SarahMB]

Thank you so much for taking the time to help me out.

So besides the higher resolution readers, are there additional reasons to use larger images?

In your experience, is there an ideal size? Does that "ideal" size differ for Kindle versus Epub formats?

Thanks again!

Sarah

[mrmikel]

To my mind, it comes down to device. If it is a 800 x 600 pixel e-ink reader, then the images should be scaled down to just a bit smaller than that. For the tablets, it is a different story.

Design for the small screens should not be the same as for the bigger ones because pull quotes etc for the big screens that work great only create reading problems in the smaller ones. Inset pictures only squeeze the text or become microscopic without detail in the smaller ones.

I have just been working on this problem with some very nice commemorative pdfs put out by the US Marine Corps. They have inset paragraphs on general topics in the middle of the text flow that are fine on a big page, but would end two or three pages later in an e-ink reader. The reader would lose their train of thought if allowed to stay in place. My ultimate solution was a link to these general topics (and back). Pictures are not super clear on e-ink readers because of the narrow grayscale range, so they need to be a big as possible. A tablet can display images in color and hi-res.

The bigger the better, but only if the machine can display them to advantage and it doesn't have to waste cpu cycles resizing, slowing everything down.

[Jellby]

Originally Posted by SarahMB

So besides the higher resolution readers, are there additional reasons to use larger images?

Future, zooming and archive.

Future: Most readers may be 600×800 today, but who knows what will be the norm in 5-10 years? Would you like to redo your book, re-scan the images, re-process them to adapt them to better screens?

Zooming: Some readers allow zooming of images, and I hope more readers will join. That means you should not feel limited by the screen size and resolution.

Archive: A low-resolution version of an image may be good enough for casual viewing, but some users may want a better version to observe smaller details, or for other uses.

[mrmikel]

I hope there will always be small readers, as I find the size most useful to me. If I were to want to study closely some of the epubs I produce which contain maps, then the smaller size is not ideal.

Start with big images and mark them in your file system as read only so they won't accidentally overwritten. Then shrink them down to suit the need. Start with non-compressed formats (like tif) so that working with them won't create artifacts of being saved as something like a jpg in the end.

Zooming is reason to use larger images, but it will mean doubling the number of pictures. Even the PRS505 allows you to pan images so you can have larger ones.

I agree with Jelby on all but one point. If you save big images to begin with, you don't have to do anything but shrink them for a smaller format. And irfanview, a free program will batch resize them for you, if they can be the same size.

But the layout of a small book is never going to be the same as that of a larger one, for reasons I cited earlier. But a small book is not the best place for an image packed book in the first place.

One way to cut the Gordian Knot may be to save off the images for larger and smaller with almost identical names. Add a 1 at the end for the larger or smaller versions, then you could do a search and replace for .jpg and replace it with 1.jpg. That way you can use the same HTML and tweak for best appearance.

[pdurrant]

The Mobipocket source format used to allow specifying different images for different resolution devices. Alas, I don't think ePub has any way of doing this.

[mrmikel]

Instead of trying to turn epubs into web pages, epub3 ought to include something useful like you report pdurrant!

[JSWolf]

Originally Posted by Jellby

Future, zooming and archive.

Future: Most readers may be 600×800 today, but who knows what will be the norm in 5-10 years? Would you like to redo your book, re-scan the images, re-process them to adapt them to better screens?

Given that there are now some 768x1024 eInk readers out there, I expect eventually they will all be like that for a 6" display.

[SarahMB]

Originally Posted by mrmikel

Design for the small screens should not be the same as for the bigger ones

I did not realize that we could specify different files for different situations and different types of readers.

[JSWolf]

Originally Posted by SarahMB

I did not realize that we could specify different files for different situations and different types of readers.

Actually, you cannot. You cannot specify to use a specific image based on the screen size. You can't do "if it's an iPhone, use the smaller image and if it's an iPad, use the larger image" Standard ePub does not work like that. You have to build your ePub to fit most situations.

But what you can do is make your images aspect ration correct for most screens and then if you make them full screen, they will fit. Like the cover or maps.

[dgatwood]

Originally Posted by JSWolf

Actually, you cannot. You cannot specify to use a specific image based on the screen size. You can't do "if it's an iPhone, use the smaller image and if it's an iPad, use the larger image" Standard ePub does not work like that. You have to build your ePub to fit most situations.

Sure you can. You can use media queries with screen dimension limits. I can't imagine why you would want to, but you can. Media queries are fully supported by both iBooks and Kindle, as well as nearly all other non-Adobe-based readers.

Caveat emptor, however. If memory serves, Adobe Digital Editions barfs on media queries, so you need to put them in a separate CSS file if you care about compatibility. ADE is violating the EPUB spec (where it says that readers must ignore unknown CSS gracefully), of course, and I've written to Adobe about it, but I'm not holding my breath for a fix. It's easy enough to work around by putting anything that makes ADE angry into a separate CSS file (and in the file that ADE doesn't ignore, specifying a set of default behavior that you can live with).

That said, I think it is well understood that ADE fully complying with published specifications is one of the signs of the apocalypse, so it is arguably good that they'll probably never get around to fixing the bug.