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Thread: Reducing File Sizes with a Batch Process

  1. #1
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    Question Reducing File Sizes with a Batch Process

    My digital cameras (all of them) use HUGE amounts of space for each image (6 Mbytes and more). I find that if I [Alt-F, V, Enter, "yes", Enter] I can compress the image to 1/3 to 1/4 its camera-size (1.4 Mytes or less) at the same resolution (pixels). I'm thinking I might be able to use the Batch Conversion as above specifying [ 100% of original size, save with original date-time ].

    Is there anything else there I should be aware of?
    Last edited by Bhikkhu Pesala; 27.09.2015 at 03:06 AM.

  2. #2
    Multiple User Jacal's Avatar
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    this isn't exactly an answer to your question, and probably not the best place for it, but perhaps you should be aware of this:

    You didn't tell what cameras and formats you are using, but I assume you are shooting in jpg format. 6 MB per image isn't considered huge this days, in raw format some cameras make images over 50 MB big. And some professional cameras even much bigger.

    If your pictures are important to you, don't do this without backing them up to a safe place first. Such conversions irreversibly decrease the amount of information, i.e. the quality of your photos. In five years, you and your children will have better monitors with much higher resolution and colour depth, better tablets, better refrigerator displays and better printers. Your current photos will look very bad then, if you decide to further degrade them. Keep them, improve them, if you want, with excellent tools available, but preserve originals. Get another disk, if you are out of space, when you can.

    Best wishes,

    Last edited by Jacal; 26.09.2015 at 10:46 PM.

  3. #3
    Moderator Enterprise User Bhikkhu Pesala's Avatar
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    If you're reducing file size to 25% of the original, then you're obviously using some JPG compression, and adding artefacts. These may not be visible unless you zoom in close, but they degrading the images significantly.

    Alt F, V is the same as Ctrl S (Save to original folder) so you must be overwriting the originals.

    The Save Icon on the IrfanView Toolbar will save images to your "My Pictures" folder without overwriting the originals, that's why it's the default.

    Open one of your camera images, and inspect its Image Properties (shortcut I). The original (estimated) image compression is highlighted in my screen shot.

    On the JPG/GIF Save dialog, take a close look at the checkboxes. The two that I have highlighted in the other screen shot are critical. If the first is not enabled you will lose Exif data saved by your Camera, such as date taken, Exposure settings, Camera model, etc. If the second is not enabled (which is probably the case from your reported results), the compression setting on the JPG slider will be used. If it is anything less than 100 you will be compressing the JPG image and losing quality.

    With the slider on 75, I can reduce a 7.61 Mbytes original to 2.22 Mbytes.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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