Cannot Install libpng12-0 on Debian

I have this resolved now. I went to the Debian forums and asked my question here, where a helpful member pointed out that libpng12-0 isn't available for Stretch (should have specified my OS version earlier, sorry). I was trying to install the Jessie version, and that just... doesn't work with Stretch right now. There's a version of libpng12-0 in Sid, currently. It should make it's way to Stretch in the near future to solve this issue.

In the meantime, I abandoned installing the Jessie libpng12-0 package, and just did the Wheezy package, which is version 1.2.49 instead of 1.2.50, which worked like a charm. Until 1.2.50 is out for Stretch, I recommend installing Wheezy's 1.2.49.

Thanks again for the help to everyone who replied and commented, you all are truly wonderful human beings!

You can download the libpng12-0 from.

http://packages.ubuntu.com/xenial/i386/libpng12-0/download for 386 architecture

and

http://packages.ubuntu.com/xenial/amd64/libpng12-0/download for 64 bits.

It looks like there's something a bit messed up with libpng12-0; it installs its .so in /lib/x86_64-linux-gnu (on amd64), but also drops a link in /usr/lib/x86_64-linux-gnu — and I think that's what's breaking here.

On my system everything is installed correctly (libpng16-16 and libpng12-0), but I also have libpng-dev installed (version 1.6), and that allows the libpng12-0 link to be resolved. If my theory is correct, you should be able to do

apt-get install libpng-dev
apt-get install libpng12-0

and have a working libpng12...