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I have iPod Touch and iPad (version 1).

I noticed some images on pdf cannot be viewed on the iBook.

Why?

Edit

The following are my pdf ebooks that cannot be viewed by iBook:

  1. Pro ASP.NET MVC 2 Framework (Expert's Voice in .NET)
  2. Learn JavaScript and Ajax with w3Schools

to be continued...

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Do you have examples of the images in question? There could be several reasons for this. –  Philip Regan Mar 7 '11 at 16:48
    
@Philip: see my update please. –  xport Mar 7 '11 at 17:20
    
Thanks, but is it the screenshots or the diagrams and illustrations that can't be viewed? –  Philip Regan Mar 7 '11 at 19:25
    
I was thinking maybe they were Flash images, which iOS doesn't do. But I don't know: Can Flash be stuck inside a PDF? –  GEdgar Nov 7 '11 at 19:05

3 Answers 3

up vote 2 down vote accepted

The trouble is in the handling of JPEG2000 image files. Some solutions are offered here. If this was your problem, it was solved with the release of iOS 5. Those images should be viewable now.

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Interesting, but does an iOS user have access to the PDFs stored in iBooks, if those are even PDFs? (They could be ePub. Then what?) –  Philip Regan Mar 7 '11 at 21:23

I'm going to attempt to answer this as best I can without detailed examples...

The screenshots and illustrations (which were most likely placed as EPS or Illustrator files) could be in some format or be corrupted in some way that the iBook PDF engine simply chooses to ignore the image (and is unarguably better than simply crashing).

PDFs are surprisingly complex documents that can be made in a number of different ways. Essentially, PDF documents are streamlined Postscript, which is a programming language unto itself. Support in PDF viewers for various features varies according to who the developed that particular viewer.

We (I) don't know what engine Apple uses to read PDFs (i.e., open source, licensed, homemade), but I would be willing to bet that if those PDFs were opened in Adobe Acrobat, that there would be no problems viewing the art (but please don't ask me how to open iBook-sourced books in Acrobat because I'm not suggesting you do that and I have no idea if for no other reason that I don't use iBooks).

Update: @Jadasc points to a definite possibility to the problem. If the art was, indeed, placed in the layouts as JPEG2000 files, then that's either bad prepress practice or the books you are looking at are ePub files. In either case, without direct access to the books to fix them, I'm not sure what can be done about it.

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You can now download the Adobe Reader for iOS. You will be able to view all .PDFs using this free app.

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