Please don't comment here, just block the bugs reported against those packages.
Sorry for dropping a comment here but isn't this bug a dupe of bug #305095?
I would say “It would be if the thing was still open” and I would very much like to know why it was closed when libpng-1.4 was unmasked to begin with. It's the moment WHEN we need the tracker most. *** This bug has been marked as a duplicate of bug 305095 ***