I needed a newer version of ImageMagick than is available on the yum packages on Amazon Linux. I tried using the remi repo but it failed with dependency errors. Here is what I did to install ImageMagick with support for PNG, JPG, and TIFF.
download the most recent package
wget http://www.imagemagick.org/download/ImageMagick.tar.gz
uncomress the package
tar -vxf ImageMagick.tar.gz
install the devel packages for png, jpg, tiff. these are dependencies of ImageMagick
sudo yum -y install libpng-devel libjpeg-devel libtiff-devel
configure ImageMagick without X11. this is a server without a display (headless) so we don't need X11
cd ImageMagick
./configure --without-x
make && make install
mission complete.
Thanks. This got me most of the way there for an upgrade on ec2 running php70! Since I was after webp support, I also installed the libwebp-devel (and giflib-devel for good measure). And, when done, I had to reinstall imagick via pecl instead of yum. Complete steps for me ended up being this: