The plugin says I’m missing something
The EWWW Image Optimizer uses jpegtran, optipng, gifsicle, and optionally pngout, pngquant, and cwebp. Odds are, most of these won’t be installed on your server, so EWWW IO comes bundled with binaries (executables) that work on most platforms (Windows, Mac OS, FreeBSD, Solaris, and common variants of Linux). But sometimes the binaries we provide don’t work on your server, and that's why you're here. If you're trying to install Pngout, that requires a different installation process. For everything else, keep reading.
Permissions and other Auto-install Problems
Before we get too far, there are a few minor issues that can break the auto-install process.
The very first thing is that EWWW IO will be trying to install the tools in wp-content/ewww/ so it needs to create that folder. If that step fails, you can create the folder yourself, or adjust permissions on the wp-content/ folder so EWWW IO can do it for you. Read more about fixing permission problems.
If you've tried to upload the plugin or the binaries manually via FTP, you may have accidentally corrupted the binaries. Make sure you use BIN (binary) mode in any FTP client, like FileZilla. You can send your debug information to our support team (below) to check for file corruption.
NOTE: if you install the tools somewhere outside your WordPress folder and want EWWW IO to ignore the bundled versions of jpegtran, optipng, etc. you can use the EWWW_IMAGE_OPTIMIZER_SKIP_BUNDLE override.
So what else can you do?
Can I build it?
ldconfig -p | grep libjpeg gcc -v make -v
Yes I Can!
1. Download the source package from the project’s website:
webp: http://downloads.webmproject.org/releases/webp/index.html (latest source tarball is usually at the bottom)
2. Unpack/extract the tarball:
tar xvzf gifsicle-1.88.tar.gz tar xvzf optipng-0.7.6.tar.gz tar xvjf pngquant-2.5.2-src.tar.bz
v = verbose (you can skip this, but I like to see what the command did)
z = gzip compression, usually when the extension is .tar.gz or .tgz
j = bzip2 compression, when the extension is .bz or .bzip2
f = file, or in other words “use the file listed after this option”
3. Configure the build
cd optipng-0.7.6/ ./configure
4. Build it
5. Install the binary
sudo make install
cp src/optipng/optipng /path-to-your-wordpress-folder/wp-content/ewww/optipng-custom