Preparing... ################################################################################################### [100%] file /usr/share/man/man5/png.5.gz from install of libpng15-1.5.12-alt1 conflicts with file from package libpng12-1.2.49-alt1 E: Error while running transaction
OK, I'll add a conflict someday. Meanwhile, consider upgrading your libpng12 to 1.2.50-alt2.
Will be fixed in 1.5.13-alt1.