When calling into the inline image copy/translation functions, the application crashes in release mode. Perhaps this is caused by a miscompile.
It might also be fixed by using a different codepath. The NEON-enhanced versions are not used but perhaps could be.
One workaround is to build Qt with optimizations disabled. In mkspecs/common/winrt_winphone/qmake.conf, change -O2 to -Od.
Another "workaround" is to not load images.