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Low quality thumbnails - bad settings or bug?

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    Low quality thumbnails - bad settings or bug?

    Hi,
    my IV 4.44 / Windows XP creates low quality thumbnails. I have checked Thumbnail option "Use Resample instead of Resize..." and unchecked "Try to load EXIF-Thumbnail...".
    I would not care about thumbnail quality in the "IrfanView Thumbnails" window, but I use the function "Save selected thumbs as HTML file" to create web photo presentation, and IV creates thumbnail JPGs for web with the same low quality. Is there any setting which could change this behaviour?
    Details: Let's have a picture 500x500:
    Click image for larger version

Name:	beatles_500x500.jpg
Views:	1
Size:	42.6 KB
ID:	84958
    Thumbnail 150x150 created by IV:
    Click image for larger version

Name:	beatles_500x500_t.jpg
Views:	1
Size:	7.1 KB
ID:	84959
    Thumbnail created using "Resize/Resample" function (from 500x500 to 146x146, then extended by frame to 150x150)
    Click image for larger version

Name:	beatles_500x500_t_resize.jpg
Views:	1
Size:	7.3 KB
ID:	84960
    Comparison in animated GIF:
    Click image for larger version

Name:	test.gif
Views:	1
Size:	12.9 KB
ID:	84961

    It looks like IV make "Resample" from 500x500 to 150x150 (high quality, I use Lanczos) and than make "Resize" (low quality) to 146x146 making thumbnail with 2 pixel frame.
    What to do with this?
    Last edited by bflmpsvz; 24.08.2017, 08:00 PM.

    #2
    Another animated gif, showing what is the problem. (Real images were magnified 4x for better visibility)

    Last edited by bflmpsvz; 18.04.2018, 11:03 AM.

    Comment


      #3
      I suggest running a batch operation to resize and change the canvas size. Overwrite the HTML page images with the results of the batch operation.

      IrfanView will use its built-in resampling algorithm for downsizing images.
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