HEIC thumbnails are displayed in the browser with incorrect rotation

[svennbg]

XnView: MP 0.99.7 (64-bits)
OS: Windows 10 Pro, Version 21H2, build 19044.1526

Effect:
Some HEIC files are displayed in the browser with incorrect rotation.
It is noticeable that the rotation symbol (highlighted in yellow) is displayed,

browser thumbnails xnview.jpg (26.42 KiB) Viewed 1183 times

.
In Windows Explorer the files are displayed correctly rotated.

thumbnails windows.jpg (10.53 KiB) Viewed 1183 times

.
In View mode the file is displayed correctly.

xnview view.jpg (56.3 KiB) Viewed 1183 times

.
Moving the files in Windows Explorer solves the problem sometimes (but not always).
Therefore, it should not be a bug of the affected HEIC files, moreover, they are displayed correctly in WIndows Explorer.



Actual behaviour (bug):
HEIC files are sometimes displayed in the browser with incorrect rotation.

Expected behaviour:
HEIC files are displayed in the browser with correct rotation (like in Windows Explorer).

Thank you very much for your help.

[xnview]

could you send me some files?

[xnview]

Thumbnails seems to be correct, if you copy these files in a new folder?

[svennbg]

Thanks for the analysis.

Copying files did not help.

What helped was to quit XnView and delete XnView.db and Thumb.db.
After that and restarting XnView the thumbnails were rotated correctly.

But when restarting XnView again, some (not all) HEIC-thumbnails were rotated wrong again.

It is noticeable that in the preview of the HEIC files the yellow marked symbol appears when the rotation is wrong.

[svennbg]

The problem seems to occur mainly when there are many HEIC files in a folder, so many thumbnails need to be created. It seems that the thumnails database has problems with too many HEIC files in a folder.

It might be a temporary solution if it would be possible to rebuild the thumbnails also for HEIC files. For the jpg files I can do this via >tools >metadata >EXIF thumbnails - rebuild.

[xnview]

The problem seems to occur mainly when there are many HEIC files in a folder, so many thumbnails need to be created. It seems that the thumnails database has problems with too many HEIC files in a folder.

how many files?

[svennbg]

the folder has in concreto 328 files