This update for libpng16 fixes the following issues:
Security issues fixed:
CVE-2019-7317: Fixed a use-after-free vulnerability, triggered when
pngimagefree() was called under pngsafeexecute (bsc#1124211).
CVE-2018-13785: Fixed a wrong calculation of rowfactor in the
pngcheckchunklength function in pngrutil.c, which could haved triggered
and integer overflow and result in an divide-by-zero while processing a
crafted PNG file, leading to a denial of service (bsc#1100687)