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Thread: How to convert the orientation of an image?

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    Unhappy How to convert the orientation of an image?

    Is it possible to convert the orientation of an image. That is portrait to landscape and vise-versa.

    Using WinXP Pro and a free version of IfranView (4.23)

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    Moderator Frank's Avatar
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    Yes, it's possibble!

    See program menu of IrfanView\Help\IrfanView Help\ → JPG Lossless Rotation

    See also program menu of IrfanView\Help\Frequently Asked Questions\


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    Default Failed attempt

    Thanks for the advice. I had to install some plugins but it still doesn't work. I understand all the steps except for "The auto-rotation works only if the EXIF the orientation tage is properly saved (not top-left)" I have no idea what that means. Please explain!!

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    Quote Originally Posted by Andem View Post
    Thanks for the advice. I had to install some plugins but it still doesn't work. I understand all the steps except for "The auto-rotation works only if the EXIF the orientation tage is properly saved (not top-left)" I have no idea what that means. Please explain!!
    Most likely that refers to some of the format tags inside a JPG file which some software does not setup properly. Thus the Portrait/Landscape recognition of such a file can not be changed simply by modifying that tag, since it doesn't have any...

    However, if you can accept the inevitable detail loss of again repacking a JPG picture (no loss will occur if you use BMP picture both for originals and results), then you can follow the very simple procedure outlined below.

    First simply display the picture in IrfanView as usual, and then press the "R" or "L" key on your keyboard to instantly twist the picture around 90 degrees right or left (so the topmost edge of the picture is twisted to become the right edge, for the "R" command). No data loss should occur at this stage, so you can twist back and forth until you're happy. (This effectively overrides any EXIF orientation, whether present as tag or just a default.)

    Next you resave the picture, using "Save As..." command. And it is here that a normal JPG picture will give losses, as JPG saving will repack the currently rendered image (not from screen, but from RAM buffer) with inevitable packing losses. Note that some data loss is inevitable if your original was a normal jpg, since losses occured when packing the file originally, and repacking it will not just retain the same loss, but will add some more.

    For such work (and most image editing work) it really is best if both original and result files are in some lossless format instead, like standard Windows BMP, rather than normal JPG.

    Normal JPG is excellent for compact end storage of pictures in access-intensive environments, such as web pages etc. But it is not a good format for preserving the full integrity of images.

    Lossless JPG is intended to fix that problem, but personally I prefer working with unpacked images, though this is clearly dependent on the relatively small volume of my image collection. With larger collections the need for packing is obvious. Just make sure that it is lossless JPG you use for images you intend to process further, with normal JPG being acceptable only for an 'end-user' context.

    Best regards: dlanor
    Last edited by dlanor; 15.05.2009 at 12:30 AM.

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    Professional User Mij's Avatar
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    Since the OP, Andem, did not mention Exif data I think you guys might be causing some confusion by introducing it.

    Open a portrait image and press the E key. If nothing happens then you do not have Exif data so forget all that stuff about Rotating by Exif. If a dialog box pops up then look what is recoded opposite Orientation. If that says Top Left then you do have EXIF data but you will still not be able to use it to rotate the image. If it says Left Bottom or Right Top though then you can use the EXIF data to auto-rotate it.

    If you cannot use EXIF data to rotate the image then you must do it yourself using Rotate left or Rotate Right from the Image menu and then Save. If your image is JPEG format you also have the alternative to use the JPG Lossless rotations from the Options Menu to Rotate Clockwise or Rotate Anticlockwise . In this case the file is saved automatically so do not Save again.

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