I'm stumbling onto more pieces as well:
The patch from the kdedevs:
Bug: https://bugs.kde.org/show_bug.cgi?id=266319
link to patch: https://bugs.kde.org/attachment.cgi?id=57257 (attached to message as well)
This may handle the gwenview problem or provide an excellent Go-By to create our own.
We will need to see if this applies and if it is fixed in TDE as well (png_read_update_info calls png_read_start_image) pngloader.cpp.
Good find!
Side note: Why every time the libpng people push a Dot Zero release everybody in the entire free/libre software world has to play Keystone Kops to fix their changes?
Darrell