I can confirm this bug on Lubuntu 23.10.
Previously, on Lubuntu 23.04, I could view HEIC images with all image viewers, using heif-gdk-pixbuf and libheif-examples.
Now, on Lubuntu 23.10, I cannot view HEIC images any more with the following image viewers:
NOT WORKING image viewers / graphics software:
gThumb
Geeqie
LXimage
GIMP
The only viewer that is working to view HEIC images now on my Lubuntu 23.10 machine is:
Eye of Mate (EOM)
I can confirm this bug on Lubuntu 23.10.
Previously, on Lubuntu 23.04, I could view HEIC images with all image viewers, using heif-gdk-pixbuf and libheif-examples.
Now, on Lubuntu 23.10, I cannot view HEIC images any more with the following image viewers:
NOT WORKING image viewers / graphics software:
gThumb
Geeqie
LXimage
GIMP
The only viewer that is working to view HEIC images now on my Lubuntu 23.10 machine is:
Eye of Mate (EOM)