Best way to resize a JPEG

Discussion in 'Digital Photography' started by Jeremy Henderson, Feb 29, 2004.

  1. I have a bunch of JPEGs I want to resize. I wonder if there's a better way
    than using Photoshop? Would it be better to use eg ImageMagick? Any tips?

    J;
     
    Jeremy Henderson, Feb 29, 2004
    #1
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  2. Jeremy Henderson

    dslr Guest

    www.irfanview.com

    freeware, and can do it as a batch for you - along with a lot of other
    stuff.
     
    dslr, Feb 29, 2004
    #2
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  3. Jeremy Henderson

    Woobie Guest

    Strongly enough, I pretend like I'm going to send the picture directly from
    the viewer and then my computer asks me if I want it resized for sending.
    Then I drag and drop that file to another folder.
    Joe
     
    Woobie, Feb 29, 2004
    #3
  4. I use Thumbs Plus 2000 to do this. Works great in interactive and in batch
    mode. Unfortunately if you want to enlarge a picture, IMHO the best
    algorithm is "Lanczos". Same is not supported by the current version of
    Thumbs Plus 2000, but Irfanview can do it.

    -Michael
     
    Michael Schnell, Feb 29, 2004
    #4
  5. Jeremy Henderson

    Alan F Cross Guest

     
    Alan F Cross, Feb 29, 2004
    #5
  6. Is there a difference between methods in terms of image quality loss? Is
    one algorithm less "lossy" than another?

    (Thanks for the suggestions, BTW, but as a Mac user not all are applicable ;-)

    J;
     
    Jeremy Henderson, Feb 29, 2004
    #6
  7. Hello, Jeremy!
    You wrote on Sun, 29 Feb 2004 09:35:49 +0100:

    JH> I have a bunch of JPEGs I want to resize. I wonder if there's a better
    JH> way than using Photoshop? Would it be better to use eg ImageMagick? Any
    JH> tips?

    This feature is available in SnapTouch as well as many others.

    Cheers, Denis Gladysh
    www.passwordrecoverytools.com - www.snaptouch.com
     
    Denis Gladysh, Feb 29, 2004
    #7
  8. Jeremy Henderson

    Uni Guest

    Lanczos isn't bad, but not as good as Genuine Fractals:
    http://www.imaging-resource.com/SOFT/GF/GF.HTM

    http://community.webshots.com/photo/42670345/47515893EPZDBe
    Upper right image GF resized to 801 x 801 - from 80 x 80 pixel icon.

    Regards,
    Uni
     
    Uni, Feb 29, 2004
    #8
  9. Jeremy Henderson

    Alan F Cross Guest

    It's not so much a question of algorithm (though they do vary). But,
    when I re-size, I like to choose the final pixel size (including any
    cropping), and then I like to choose the compression factor - very
    little compression (large file, good quality), a lot of compression
    (smaller file, poor quality), or something in between. All depends on
    application.
     
    Alan F Cross, Feb 29, 2004
    #9
  10. Jeremy Henderson

    Ron Hunter Guest


    True, and much depends on need, and final use. Hardly worth preserving
    resolution that can't be displayed, or making a file that is so large
    only cable/dsl/t? users will view the picture online.
     
    Ron Hunter, Feb 29, 2004
    #10
  11. Jeremy Henderson

    Jürgen Eidt Guest

    Jürgen Eidt, Feb 29, 2004
    #11
  12. Jeremy Henderson

    FredBillie Guest

    << From: Jeremy Henderson
    Date: Sun, Feb 29, 2004 5:04 AM
    Message-id: <>

    Is there a difference between methods in terms of image quality loss? Is
    one algorithm less "lossy" than another?

    (Thanks for the suggestions, BTW, but as a Mac user not all are applicable ;-)

    J;
     
    FredBillie, Mar 1, 2004
    #12
  13. Jeremy Henderson

    Lucas Tam Guest

    Yes, different JPEG algorithms have different characteristics. However, the
    differences are quite small and generally not noticable to most people.
    Unless you're extremely fussy, everyday graphics programs JPEG algorithm
    will do.
     
    Lucas Tam, Mar 1, 2004
    #13
  14. Lanczos isn't bad, but not as good as Genuine Fractals: AFAIK, Genuine Fractals is only available as photo shop plug i. I don't have
    photo shop. Moreover AFAIK, it's very expensive. Moreover I heard opinions
    that rate Genuine Fractals lower than another (much faster and cheaper) plug
    in (which I could not test either).

    -Michael
     
    Michael Schnell, Mar 5, 2004
    #14
  15. SNIP
    IMHO, Qimage does a more realistic (less posterized look) job, and at a MUCH
    better price.

    Bart
     
    Bart van der Wolf, Mar 6, 2004
    #15
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