Giorgos Sarigiannidis

Slimage uses <a href="https://github.com/tjko/jpegoptim" rel="nofollow ugc">jpegoptim</a> and <a href="http://optipng.sourceforge.net/" rel="nofollow ugc">optipng</a> to compress your images during upload. It will compress the thumbnails that WordPress generates but will leave the original file intact, so that you can safely restore your changes if necessary.
The plugin will also allow you to manually set the compression level and quality on a per-image basis. That way you have absolute control on how much quality you are willing to sacrifice in order to achieve better performance improvements, which can be handy if you want to pass the Google PageSpeed test.
Using it in conjuction with the <code>wp media regenerate</code> command of <a href="https://wp-cli.org/" rel="nofollow ugc">WP-CLI</a> or with some thumbnail regeneration plugin, you can bulk optimize your photos and even experiment until you find the combination of quality/size that suits you.
To use the plugin you need to have <code>jpegoptim</code> and <code>optipng</code> installed on your server and make sure that PHP <code>shell_exec()</code> function isn’t disabled in your <code>php.ini</code>.
<h4>Features</h4>
<ul>
<li>Compress an image during upload.</li>
<li>You can set a default level of compression for all newly uploaded images.</li>
<li>You can override that compression level on a per-image basis.</li>
<li>You can use all the available options of jpegoptim and optipng.</li>
<li>Combining it with some image regeneration tool, you can bulk compress your existing images.</li>
<li>The plugin leaves the original image intact, so that any change that you make can be reversible.</li>
</ul>

Slimage

A WordPress plugin that uses jpegoptim and optipng to compress images during upload, allowing you to override the compression level and quality on a p …

Raffael Jesche

Automatically optimize uploaded images (jpg, png, gif, webp, svg, avif) using the <a href="https://github.com/spatie/image-optimizer" rel="nofollow ugc">Spatie image-optimizer library</a> and binary files on your host system.
New uploaded images with all image sizes (thumbnails) will be optimized automatically.
Previously uploaded images can be updated in two ways:
<ol>
<li>Use the command line interface (cli) and run <code>wp media regenerate</code>, which also triggers the optimization chain. If you don’t have cli access, some other plugin, that regenerates existing thumbnails should work, too (not tested, yet).</li>
<li>The media library has a new column “File size” in the list view, which displays the new and the old file size. If an image is not optimized, there is a link named “Optimize” to run the optimizer directly.</li>
</ol>
Warning: Images are replaced with the optimized ones. Create a backup before testing this plugin. If this is a deal-breaker for you, don’t use it.
Important: If the needed binary files aren’t installed, this plugin won’t optimize anything. Don’t use it, if you don’t know, how to install them or if your web hoster doesn’t provide them.
Notice: WordPress has no support for SVG files. Technically this plugin can optimize them, but I didn’t run any tests with plugins, that add SVG support to WordPress. I was able to optimize svg files automatically in a local test setup (see <a href="https://codeberg.org/raffaelj/wordpress-another-simple-image-optimizer/src/branch/main/tests/prepare-and-run-tests.sh" rel="nofollow ugc"><code>prepare-and-run-tests.sh</code> in the tests folder</a> and search for <code>enable_svg_avif_upload</code>).
For more information and notes about development, checkout the <a href="https://codeberg.org/raffaelj/wordpress-another-simple-image-optimizer/src/branch/main/README.md" rel="nofollow ugc">project README.md file on Codeberg</a>
<h3>Requirements</h3>
<ul>
<li>PHP function <code>proc_open</code> must be enabled (some web hosts disable it via <code>php.ini</code>)</li>
</ul>
<h3>Settings</h3>
Quality settings can be adjusted with constants in <code>wp-config.php</code>:
Set quality for resizing images (GD/Imagick)
<ul>
<li><code>define('ASIO_RESIZE_QUALITY_JPEG', 100); // default: 82</code></li>
<li><code>define('ASIO_RESIZE_QUALITY_WEBP', 100); // default: 86</code></li>
</ul>
Set quality of optimizers
<ul>
<li><code>define('ASIO_QUALITY_JPEGOPTIM', 90); // default: 85</code></li>
<li><code>define('ASIO_QUALITY_PNGQUANT', 90); // default: 85</code></li>
<li><code>define('ASIO_QUALITY_CWEBP', 85); // default: 90</code></li>
<li><code>define('ASIO_QUALITY_AVIFENC', 70); // default: 63</code></li>
</ul>
<h3>Optimization tools</h3>
Spatie image-optimizer will use these optimizers if they are present on your system:
<ul>
<li><a href="https://github.com/tjko/jpegoptim" rel="nofollow ugc">JpegOptim</a></li>
<li><a href="http://optipng.sourceforge.net/" rel="nofollow ugc">Optipng</a></li>
<li><a href="https://pngquant.org/" rel="nofollow ugc">Pngquant 2</a></li>
<li><a href="https://github.com/svg/svgo" rel="nofollow ugc">SVGO 1</a></li>
<li><a href="http://www.lcdf.org/gifsicle/" rel="nofollow ugc">Gifsicle</a></li>
<li><a href="https://developers.google.com/speed/webp/docs/precompiled" rel="nofollow ugc">cwebp</a></li>
<li><a href="https://github.com/AOMediaCodec/libavif/blob/main/doc/avifenc.1.md" rel="nofollow ugc">avifenc</a></li>
</ul>
At least jpegoptim and optipng should be installed.
You can find information about how to install the binary files in the <a href="https://github.com/spatie/image-optimizer#optimization-tools" rel="nofollow ugc">Spatie image-optimizer README.md file</a>.

Another simple image optimizer

Automatically optimize uploaded images using the Spatie image-optimizer library and binary files on your host system (e. g. jpegoptim, optipng)

Slimage vs Another simple image optimizer