This update for libpng12 fixes the following issues:
Update to version 1.2.59 (jsc#PED-16191).
png_set_tRNS and png_set_PLTE can lead to arbitrary code
execution (bsc#1260754).png_set_PLTE, png_set_tRNS and png_set_hIST can lead to corrupted chunk data
and potential heap information disclosure (bsc#1261957).