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  1. #1
    New Lounger
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    I have imported all my pictures (30Gb) to my new Windows 7 laptop. Something is quietly adding a few bytes to the EXIF information of all the JPEGs and thus altering the modification date of the files. I can't see any differences in the EXIF information. It is going through the folders and altering them in name order.

    To make things worse, I keep my desktop and laptop synchronised so all these pictures are being copied back to my desktop (because they have new modification dates and different sizes).

    This is happening in the background - I haven't got the pictures open in any application. No other applications are running, Windows Media Player is not open. I have an up-to-date virus checker (MSE) and Windows firewall is active.

    I suspect it is some function of Windows Media Player, updating libraries?

    What is going on? How can I stop it?

    Many thanks

  2. #2
    Gold Lounger Roderunner's Avatar
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    Hi JP, welcome to the Lounge
    I believe its standard practice for your laptop to modify the pictures info to the date they were transfered. I don't think the size would be changed as PC's resize them automatically to fit the monitor on which they are being viewed. What program do you use to view them. ?
    O wad some Power the giftie gie us, to see oursels as ithers see us!

  3. #3
    Super Moderator satrow's Avatar
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    That sounds like it may be attributed to the Windows Search database.

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    Quote Originally Posted by Roderunner View Post
    I believe its standard practice for your laptop to modify the pictures info to the date they were transfered.
    What does this and why?


    Quote Originally Posted by Roderunner View Post
    I don't think the size would be changed as PC's resize them automatically to fit the monitor on which they are being viewed. What program do you use to view them. ?
    That's right, it is the size of the file that is being modified, not the size of the picture. A few bytes are being added to the EXIF data for each picture.

    I haven't viewed any of them yet. I will probably use Irfanview and Corel Photo Album.


    Quote Originally Posted by Andy Rowlands View Post
    That sounds like it may be attributed to the Windows Search database.
    Windows Search doesn't alter file dates or add to them, surely?

    Thanks for your help.

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    Gold Lounger Roderunner's Avatar
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    Quote Originally Posted by JP Coetzee View Post
    What does this and why?
    I'm not sure, but hope this helps.

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    O wad some Power the giftie gie us, to see oursels as ithers see us!

  6. #6
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    Quote Originally Posted by Roderunner View Post
    I'm not sure, but hope this helps.
    Many thanks, but that's not the problem because it is not the "Last Accessed" field which is changing.

    It's something hidden doing this.

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    Super Moderator bbearren's Avatar
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    Whenever you copy a file (picture or whatever) the date shown after the file name in Explorer is the date that you copied the file, unless you have disabled the "last accessed" behavior of NTFS. If you have copied a bunch of files (photos) to your laptop, the date that you copied them will be the date shown for the file.

    At any rate, the culprit is NTFS. Bear in mind that the NTFS file system waits for slack time on the CPU/system to do its routine file system maintenance/updates. If you copied a gob of pictures, it will take NTFS some time to update all the file system data related to the files in question; it won't do anything during hibernation, or when the system is shut down; it will wait for available CPU/system time when the laptop is up and running. While it is waiting for available slack time, it keeps the update information stashed in a temporary area of the MFT. If there is quite a bit of file fragmentation, it will take longer, since it will update each fragment in order to update the entire file.

    Also, file information/statistics are part of the file, so the size can change without any change to the file itself. And again, if there are many fragments, the file information/statistics will be larger, as each fragment must have matching information in order to put the file together when you call for it.
    Create a fresh drive image before making system changes, in case you need to start over!

    "The problem is not the problem. The problem is your attitude about the problem. Savvy?"—Captain Jack Sparrow "When you're troubleshooting, start with the simple and proceed to the complex."—M.O. Johns "Experience is what you get when you're looking for something else."—Sir Thomas Robert Deware.
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  8. #8
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    Quote Originally Posted by bbearren View Post
    Whenever you copy a file (picture or whatever) the date shown after the file name in Explorer is the date that you copied the file, unless you have disabled the "last accessed" behavior of NTFS. If you have copied a bunch of files (photos) to your laptop, the date that you copied them will be the date shown for the file.
    You are right but I am not looking at the "Accessed" column - I am looking at the "Modified" column, which should not change. And the file sizes have changed - extra EXIF data is being added to the JPEGs. Something is tweaking my files!

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    Plutonium Lounger Medico's Avatar
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    Quote Originally Posted by bbearren View Post
    bbearren states:

    At any rate, the culprit is NTFS. Bear in mind that the NTFS file system waits for slack time on the CPU/system to do its routine file system maintenance/updates. If you copied a gob of pictures, it will take NTFS some time to update all the file system data related to the files in question; it won't do anything during hibernation, or when the system is shut down; it will wait for available CPU/system time when the laptop is up and running. While it is waiting for available slack time, it keeps the update information stashed in a temporary area of the MFT. If there is quite a bit of file fragmentation, it will take longer, since it will update each fragment in order to update the entire file.

    Also, file information/statistics are part of the file, so the size can change without any change to the file itself. And again, if there are many fragments, the file information/statistics will be larger, as each fragment must have matching information in order to put the file together when you call for it.
    JP, I believe your question was answered here. The info stored by the system for the file actually changes the size of the file as it stores this info within the file while awaiting the slack time to adjust the date accessed info. and the size can change as the file stores its own statistics as part of the file for future reference.
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  10. #10
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    Quote Originally Posted by Ted Myers View Post
    JP, I believe your question was answered here. The info stored by the system for the file actually changes the size of the file as it stores this info within the file while awaiting the slack time to adjust the date accessed info. and the size can change as the file stores its own statistics as part of the file for future reference.
    Thanks for your continued help. I'm finding this hard to believe because:

    1. It is only happening to my pictures. Why not all my other copied-over files? I have copied over .docs, .pubs, .htmls, .exes etc etc.

    2. What would you expect to happen when these altered files are re-synchronised (copied back) to my NTFS desktop PC?

  11. #11
    Gold Lounger Roderunner's Avatar
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    JP, I have just looked at my pictures on my desktop, compared them with the entry in my laptop and the details as to dimensions and size are exactly the same even though the screen resolution is different.
    O wad some Power the giftie gie us, to see oursels as ithers see us!

  12. #12
    Super Moderator satrow's Avatar
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    How about running some tests on a new photo using HashTab, it may help find the cause of this apparent anomaly.

  13. #13
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    Quote Originally Posted by Roderunner View Post
    JP, I have just looked at my pictures on my desktop, compared them with the entry in my laptop and the details as to dimensions and size are exactly the same even though the screen resolution is different.
    Yes, the dimensions and size of the pictures themselves will always be the same. But there is additional data in those picture files called metadata which is not part of the actual picture. It holds information on (for example) exposures, apertures, camera name etc etc. Something is adding to the metadat in the file, increasing it's size on disk.

    Quote Originally Posted by Andy Rowlands View Post
    How about running some tests on a new photo using HashTab, it may help find the cause of this apparent anomaly.
    How will it help?

  14. #14
    Super Moderator satrow's Avatar
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    Cryptographic hashes have a lot of uses, some of which are: detecting data changes, storing or generating passwords, making unique keys in databases and ensuring message integrity.
    From A brief history of Cryptographic Hashes/MD5

    I'd shoot a new picture, hook up a cardreader to view the file in Explorer. Make the original file Read-only then copy it over to your hard drive then uncheck the Read-only attribute on the copied file. Use the HashTab properties extension to check the file and compare it to the original. The hashes and files should be identical.

    If you check the copied file's hash periodically over a few hours or days, you'll be able to tell if the file has been altered.

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    Quote Originally Posted by JP Coetzee View Post
    Many thanks, but that's not the problem because it is not the "Last Accessed" field which is changing.

    It's something hidden doing this.
    If you want to dig into this you can use a free tool such as Process Monitor to find out what is accessing your files.

    Joe
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