Lingering PNG error solution:
PNG errors - Manual install
cd /usr/lib/x86_64-linux-gnu/*** your directory may vary
apt-get update
apt-get upgrade
apt-get autoremove
sudo apt-get install libtool autoconf build-essential pkg-config automake tcsh
wget http://archive.ubuntu.com/ubuntu/pool/main/libp/libpng/libpng_1.2.54.orig.tar.xz
tar -xvf libpng_1.2.54.orig.tar.xz
cd libpng-1.2.54
./autogen.sh
./configure
make -j8
sudo make install
sudo ldconfig