3 Replies Latest reply: Nov 5, 2012 4:25 PM by K T
vinnyvg Level 4 Level 4

There seems to be lots of confusion about image sizes and Apple iBookstore Support  et al simply state that images should not be greater than 2 megapixels.


IBook Author Help > Photos and other images,  states:-

Important:  When you export your book for distribution outside the iBookstore, images are automatically scaled to a width of 2048 pixels, which is optimized for iPad with Retina display. Readers can view these images on other iPad models, but the viewing experience might be slower. You can improve the viewing experience on iPad models without Retina display by using images no wider than 1024 pixels.


http://support.apple.com/kb/HT5117 states:-


Publishing to the iBookstore:

If most of your readers will be using the original iPad, scale down images in Interactive Image widgets to a width of 2048 pixels and all other images to a width of 1024 pixels.

Previewing on iPad, or exporting for distribution outside the iBookstore:

You can improve the viewing experience on iPad models without Retina display by scaling down images in Interactive Image widgets to a width of 2048 pixels and all other images to a width of 1024 pixels.iBA help deals with exporting  books OUTSIDE the store and simply advises that you can  help none Retina viewers by having a smaller image.  No help at all really - but suggests that the use of images 2048 is OK. that would indicate 2048 x 1536 or 1496. No mention of what resolution should be used.

iBookstore support basically reapeat this. 

So  to ease life in getting books accepted,  should we all use 1024 x 768 @72ppi for iPad & iPad 2 and now iPad mini. ????
and use 2048 x 1536 @ ??   for The New iPad Retina display!

Both fail to mention HOW the books author would know which iPad a buyer/viewer will be using.  Also if "we" only use 1024 x 768, those with Retina do not get an "enhanced viewing experience".

For a company that deals entirely with  devices that use logical programming - there seems very little logic  applied when it comes to dealing with a section of their business which by issueing iBA Free and wacking 30% of the top, must be adding to the $billions already stacked away in a corner somewhere.

iBA makes eBooks for use/display on iPads only. For months now since iBA  became available, one of the  most common requests on this forum is help with....image sizes.

It seems reasonable  now when Retina is in use and eventually the iPad and iPad 2 will fade away - ditto the new none retina mini and ALL Apple devices and  computers will be retina. So why not plan now!  Surely images in shoudl be geared to deal with Retina displays. IF  Apple would  take that line maybe  "Support" would have less work dealing with requests for help about images IF Apple accept that the next Stephen King may not have a clue how to deal with adjusting images sizes and simply state the required dimentions.

I make photo books and use 2048 x 1496 @150ppi - so far ten free books have gone into the store.

The suggestion about  images  for retina display as "standard" as been  sent as feedback.

iMac (21.5-inch Mid 2011)
  • Yleb Level 1 Level 1

    to my mind the first confusion with images size is about dpi or ppp..

    dpi in photoshop is only important when you work in cm or pouce for print but for screen 1 pixel = 1 pixel and in 72 dpi 1 pixel = 1 point

    when you work for screen, prepare images is always a compromise between quality and weight and depend of your image (a lot of detail or flat colors...) and reader's equipment.. i hope that first ipad are not all in dustbin ;-) it depends also if image can be enlarged by reader or fixe.

    so support's answer is a compromise that works not so bad in my opinion but you have to experience it for your work.

    to finish, an image less then 2 million pixels in 1,3/ratio = 1600 x 1200

  • vinnyvg Level 4 Level 4

    For all those who are still confused by Apples image restrictions / requirements...


    In the new Template chooser after the recent updates is "Antique". This template has a Chapter background image ( the olde world print of sailing ships in blue litho print style ). This print when opened in PS is 2771 x 1506 @72ppi. 2771x1506=4,173,126 pixels.This implies  Apple supply a book which does not comply with its own requirements!


    Higher  image resolution applied to printed photo inmages, make the image sharper. If for example you wanted to print a wall poster 45inches  wide, the  image needs needs a higher resolution to cater for the size, BUT the same image used for a 45" poster will print 4.5" wide print on your own printer!


    iBA full page is deemed to be 1024 x 748. resolution from Apple is 72ppi. An image with those specifications will be OK in iPad & iPad 2 - but not so sharp on a Retina display especially if zoomed larger on screen


    Now it seems 2048 x 1496 - double the original image size is suggested for Retina.


    You  can change an image in PS i.e. 1024 x 748 and change resolution to 144. PS will double the pixel size as you change the resolution. OK, just change pixel sizes back to 1024 x 748 and reolution is now 144.

    That indicates a sharper image which will be suitable for retina display and in fact all current iPad models.


    Today my 11th photo book was notified as available  in the iBook Store, all my images were pre-formatted at 2048 x 1496 @ 150ppi.   ( 2048 x 1496 = 3.063,808 pixels!)


    During delivery there were no issues flagged and after delivery no tickets.


    So I suggest all those folk pondering images sizes follow my example, which  is now proved to be accepatble!


    One thing puzzles me though, I dont use all images as full page and  they can  be masked down to - say - 250 x 200.  Should  just  make an image to fit the size I  want to display ??

  • K T Level 7 Level 7

    Anything beyond 72 dpi is wasted. Don't bother going beyond that number.