Windows Vista Forums

Jpeg compression
  1. #1


    Skynet Guest

    Jpeg compression

    Eveytime i edit and save images with WLPG the size of them decreases of
    about 50%. For example a 7mpx picture which takes about 3mb before being
    edited, takes 1.5-1.7mb after the operation.
    I suppose that WLPG uses a high compression factor, even if pictures look
    good the same.
    To keep the greatest quality should i use a true image editor where i can
    choose a custom jpeg compression or trust WLPG?
    Thanks




      My System SpecsSystem Spec

  2. #2


    Troy Barnes \(MSFT\) Guest

    Re: Jpeg compression

    Wow, that is not the expected behavior. Can you tell me the steps I need to
    follow to reproduce the same behavior? I have an 8mpx photo. What kind of
    editing to you do to the photo? Remove red eye? Adjust Color? Also, do
    you have an original 7mpx photo where you see this problem that you can
    share with me?

    --
    Troy Barnes
    Microsoft

    This posting is provided "AS IS" with no warranties, and confers no rights.

    "Skynet" <skynet@xxxxxx> wrote in message
    news:10181DBB-8C26-417B-9894-F566221275A6@xxxxxx

    > Eveytime i edit and save images with WLPG the size of them decreases of
    > about 50%. For example a 7mpx picture which takes about 3mb before being
    > edited, takes 1.5-1.7mb after the operation.
    > I suppose that WLPG uses a high compression factor, even if pictures look
    > good the same.
    > To keep the greatest quality should i use a true image editor where i can
    > choose a custom jpeg compression or trust WLPG?
    > Thanks

      My System SpecsSystem Spec

  3. #3


    John Inzer Guest

    Re: Jpeg compression

    Troy Barnes (MSFT) wrote:

    > Wow, that is not the expected behavior. Can you tell me the steps I
    > need to follow to reproduce the same behavior? I have an 8mpx photo.
    > What kind of editing to you do to the photo? Remove red eye? Adjust
    > Color? Also, do you have an original 7mpx photo where you see this
    > problem that you can share with me?
    ==============================
    Apparently the compression algorithms
    used in various brands of digital cameras
    are not all the same. I downloaded a few
    sample JPEGs from Steve's Digicams
    and used Auto Adjust on each one in
    WLPG.

    I found the results to be interesting:
    (all from 7MP cameras 3072 x 2304)

    Canon before : 3.05 MB after : 1.52 MB
    Fuji before : 3.19 MB after : 2.05 MB
    Kodak before : 2.14 MB after : 1.49 MB
    Olympus before : 3.32 MB after : 1.51 MB
    Sony before : 2.95 MB after : 1.07 MB

    If you use the Revert option to undo the edit...
    the original file size is also restored.

    --

    John Inzer
    Digital Media MVP

    Notice
    This is not tech support
    I am a volunteer

    Solutions that work for
    me may not work for you

    Proceed at your own risk



      My System SpecsSystem Spec

  4. #4


    Skynet Guest

    Re: Jpeg compression



    "Troy Barnes (MSFT)" <troyb@xxxxxx> ha scritto nel messaggio
    news:B24ABE5D-1E01-49DC-9287-B4FACA7F0391@xxxxxx

    > Wow, that is not the expected behavior. Can you tell me the steps I need
    > to follow to reproduce the same behavior? I have an 8mpx photo. What
    > kind of editing to you do to the photo? Remove red eye? Adjust Color?
    > Also, do you have an original 7mpx photo where you see this problem that
    > you can share with me?
    >
    > --
    > Troy Barnes
    > Microsoft

    You can do a simple test using this picture:

    http://www.thoosje.com/vista-wallpap...lpapers(3).jpg

    Open in with windows live photogallery, go to edit and choose "auto adjust".
    Then exit WLPG to let it to save the picture and go to your hd where you
    saved the image: you will see that it has been reduced from 1597kb to 497.
    Where that megabyte has gone?
    Picture look nice the same, but WLPG uses a too high jpeg compression.


      My System SpecsSystem Spec

  5. #5


    osu9400 Guest

    Re: Jpeg compression

    you're right, we need a slider like photoshop has when saving jpgs.

    "Skynet" <skynet@xxxxxx> wrote in message
    news:BF15E014-9565-4612-90AB-415D2C07F34F@xxxxxx

    >
    >
    > "Troy Barnes (MSFT)" <troyb@xxxxxx> ha scritto nel messaggio
    > news:B24ABE5D-1E01-49DC-9287-B4FACA7F0391@xxxxxx

    >> Wow, that is not the expected behavior. Can you tell me the steps I need
    >> to follow to reproduce the same behavior? I have an 8mpx photo. What
    >> kind of editing to you do to the photo? Remove red eye? Adjust Color?
    >> Also, do you have an original 7mpx photo where you see this problem that
    >> you can share with me?
    >>
    >> --
    >> Troy Barnes
    >> Microsoft
    >
    >
    > You can do a simple test using this picture:
    >
    > http://www.thoosje.com/vista-wallpap...lpapers(3).jpg
    >
    > Open in with windows live photogallery, go to edit and choose "auto
    > adjust".
    > Then exit WLPG to let it to save the picture and go to your hd where you
    > saved the image: you will see that it has been reduced from 1597kb to 497.
    > Where that megabyte has gone?
    > Picture look nice the same, but WLPG uses a too high jpeg compression.

      My System SpecsSystem Spec

  6. #6


    Troy Barnes \(MSFT\) Guest

    Re: Jpeg compression

    Thanks for your input on this,
    Based on what you posted you think the adjusted (smaller in file size) photo
    is still nice, right? It seems like with this photo it is easier to get
    good compression because the file has much of the same color throughout the
    entire scene. This would mean less data is needed when compressed. If you
    were to test this with a photo with more colors you would not see such a
    file size reduction.

    I guess it comes down to your happiness with photo appearance. If it still
    looks good and it saves some space then it is good, right? If you don't
    want to have that much compression you can go to the File menu and choose
    "Revert to Original (CTRL + R)" and the original file will be restored. We
    will consider an option to change the jpeg compression in the future.

    --
    Troy Barnes
    Microsoft

    This posting is provided "AS IS" with no warranties, and confers no rights.

    "Skynet" <skynet@xxxxxx> wrote in message
    news:BF15E014-9565-4612-90AB-415D2C07F34F@xxxxxx

    >
    >
    > "Troy Barnes (MSFT)" <troyb@xxxxxx> ha scritto nel messaggio
    > news:B24ABE5D-1E01-49DC-9287-B4FACA7F0391@xxxxxx

    >> Wow, that is not the expected behavior. Can you tell me the steps I need
    >> to follow to reproduce the same behavior? I have an 8mpx photo. What
    >> kind of editing to you do to the photo? Remove red eye? Adjust Color?
    >> Also, do you have an original 7mpx photo where you see this problem that
    >> you can share with me?
    >>
    >> --
    >> Troy Barnes
    >> Microsoft
    >
    >
    > You can do a simple test using this picture:
    >
    > http://www.thoosje.com/vista-wallpap...lpapers(3).jpg
    >
    > Open in with windows live photogallery, go to edit and choose "auto
    > adjust".
    > Then exit WLPG to let it to save the picture and go to your hd where you
    > saved the image: you will see that it has been reduced from 1597kb to 497.
    > Where that megabyte has gone?
    > Picture look nice the same, but WLPG uses a too high jpeg compression.

      My System SpecsSystem Spec

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