How to access the picture file on iPod/iPhone?

When I connect the iPod (or iPhone) to the Windows PC,

it look like an USB drive, but I can't open a file on it because I can't know the correct file path.

I was also unable to drop the file to my application because the drag source does not have CF_HDROP.

Some applications can open a file on iPod, but it was a copy on the local temp folder.

screenshot http://img862.imageshack.us/img862/5396/ipodx.png

My question is ..

1. How ca开发者_高级运维n I directly (programmatically) open and read the picture file on iPod?

2. If I double click on it (or right click and select Preview menu),

   it launches Windows Photo Viewer -- it is not my default picture viewer.

   Can I change the file (.PNG) association to other application?

   What's the viewer application's requirement to be a default viewer for files on ipod?

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1. Applications that do that use Picture Transfer Protocol (PTP). On Windows Microsoft implements many interfaces as part of Windows Image Acquisition (WIA). Read more here: http://msdn.microsoft.com/en-us/library/ms630344(v=VS.85).aspx

2. http://support.microsoft.com/kb/307859 or manually edit registry at HKEY_CLASSES_ROOT\.png

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Try the iPhoneBrowser program. It should give you a fair idea of the path.

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From everything I've read I don't think Apple gives you access to the file system on the iPhone / iTouch / iPad; they want you to use iTunes to transfer files back and forth. I believe the Android and Windows Phone environments have similar restrictions. (If you "jailbreak" or "root" your device that's obviously a different story, which is why many such utilities explicitly state they only work on rooted devices.)

In part, this is a security precaution: if it were possible to directly access the file system on the mobile device it would be that much easier for someone to plant malware on your phone or PDA.

For this reason, updates to the various mobile OSes frequently include changes to (1) make jailbreaking more difficult and/or (2) close the loopholes that allow software like the iPhoneBrowser to work.

Some of the portable music players that use (Windows) Media Player have similar limitations. For example, I had a Sansa m100 (I think) where I could just drag files to the device and the playlist would automatically get updated; on at least some of the newer models (eg the c200) you have to use Media Player to download content. Which to me is annoying since there doesn't seem to be a way to use Media Player to delete content from the device.

There probably are APIs to do this sort of thing, but I would guess they're somewhat specific to the platform you're using -- ie I don't think you're going to be able to just use CreateFile() or something like that.