[Bug in XnConvert] XnConvert - Rotate based on EXIF orientation

[sx090]

Hi all,

I've been using XnViewMP for organizing and adjusting images, and I find the functions “Rotate based on EXIF orientation field” and afterwards “Rebuild EXIF thumbnails” particularly useful there.

I now want to use XnConvert to automate batch image compression (and re-encoding to JPGli) and would like to know:

Can XnConvert automatically rotate images based on the EXIF orientation field, just like XnViewMP does? If so, where is the option located?
I mean, rebuilding the embedded thumbnail seems possible, directly within hte JPG format settings... But I can't find the setting to rewrite the orientation of the Image...

EDIT: Check my Post #3 - it seems XnConvert does NOT recalculate the embedded EXIF Thumbnail, original files from my Samsung S23.

Thanks in advance for your help!

Best regards,
Björn

EDIT:
Sample files
https://www.dropbox.com/scl/fo/tcy5yo0c ... ft6ud&dl=0

[cday]

Can XnConvert automatically rotate images based on the EXIF orientation field, just like XnViewMP does? If so, where is the option located?
I mean, rebuilding the embedded thumbnail seems possible, directly within hte JPG format settings... But I can't find the setting to rewrite the orientation of the Image...

That seems to be supported in Actions > Transform > Rotate where a radio button is provided to select it...

I want to make sure that after compression, the images are still correctly oriented and have updated thumbnails for better previewing in file explorers.

I can't comment directly on that, but you should now hopefully be able to check actual operation...

[sx090]

Thank you for your help - I ran some tests and I can't seem to properly understand the combination of different checkboxes - it seems buggy to me overall.

I have two input images from my Samsung S23, one in landscape, one in portrait mode. See here (rotation icon):



It seems to NOT matter whether I add the Action "Transform > rotate -> EXIF orientation" or uncheck it:
In both cases, the image itself is actually rotated and the EXIF orientation shows "Top Left" afterwards. So this part looks good and fine (even though I could imagine some ppl don't want the EXIF tag to be "reset" - but at least for me: This is exactly what I wanted).

The "buggy part" is the Thumbnail: Under JPG format settings, I activated to re-calculate the EXIF thumbnail, but the image thumbnail shows wrongly orientated both in XnConvert and XnViewMP after my compression.


It seems the EXIF thumbnails are not re-calculated properly...

It looks like this (you can clearly see, the orientation was reset to "Top left" but the Thumbnail is wrong:



I also verified it when I ran this command before/after: The extracted thumbnails are binary-identical before/after

Code: Select all

exiftool -b -ThumbnailImage 20250622_111344.jpg > thumbnail_before.jpg
... run xnconvert here ...
exiftool -b -ThumbnailImage 20250622_111344.jpg > thumbnail_after.jpg