ShortPixel

reSmush.it

The reSmush.it Image Optimizer is a free WordPress image compressor and optimizer plugin which allows you to smush your website’s images so that they load faster. 
The plugin is super easy to use (just 2 clicks!), supports JPG, PNG and GIF image formats and can be used to bulk optimize current (past) images and automatically optimize all new images. 
You can also adjust the optimization levels and exclude certain images. 
Since its launch more than 9 years ago, <a href="https://resmush.it" rel="nofollow ugc">reSmush.it</a> has become the preferred choice for WordPress image optimization as it allows you to smush the images for free. 
reSmush.it image optimization service works on <a href="https://resmush.it/tools/" rel="nofollow ugc">various CMS platforms</a> (WordPress, Drupal, Joomla, Magento, Prestashop, etc.) and is used by more than 400,000 websites worldwide. 
reSmush.it has earned the reputation of being the best free, fast and easy image optimization plugin out there 🙂
Features: 
– Free bulk image compressor 
– Automatic image optimization on upload 
– Keep or remove EXIF data 
– Image quality selector 
– Exclude images from optimization 
– Powerful and free image optimizer API 
– Customizable settings for image quality 
– Automatic image optimization with CRON 
– Backup and restore original images 
– Image statistics 
– File logging for developers
Other plugins by <a href="https://shortpixel.com" rel="nofollow ugc">ShortPixel</a>:
<ul>
<li><a href="https://wordpress.org/plugins/fastpixel-website-accelerator/" rel="ugc">FastPixel Caching</a> – WP Optimization made easy</li>
<li><a href="https://wordpress.org/plugins/shortpixel-image-optimiser/" rel="ugc">ShortPixel Image Optimizer</a> – Image optimization & compression for all the images on your website, including WebP & AVIF delivery</li>
<li><a href="https://wordpress.org/plugins/shortpixel-adaptive-images/" rel="ugc">ShortPixel Adaptive Images</a> – On-the-fly image optimization & CDN delivery</li>
<li><a href="https://wordpress.org/plugins/enable-media-replace/" rel="ugc">Enable Media Replace</a> – Easily replace images or files in Media Library</li>
<li><a href="https://wordpress.org/plugins/regenerate-thumbnails-advanced/" rel="ugc">reGenerate Thumbnails Advanced</a> – Easily regenerate thumbnails</li>
<li><a href="https://wordpress.org/plugins/resize-image-after-upload/" rel="ugc">Resize Image After Upload</a> – Automatically resize each uploaded image</li>
<li><a href="https://wordpress.org/plugins/wp-svg-images/" rel="ugc">WP SVG Images</a> – Secure upload of SVG files to Media Library</li>
</ul>

reSmush.it : The original free image compressor and optimizer plugin

the plugin is great, but the service itself is remote so you depend on the network, this causes many stability issues and in the past weeks ițs been horrible.

many stability

Unfortunately I had a lot of problems with resmush.it. Even running it on a fairly new and clean website with few other plugins. 

1. Resmush.it constantly had problems connecting to a server.

2. When I tried uploading an image I sometimes had to wait for minutes before smushed it. I don't know whether it had anything to do with the server connection issue.

3. When I tried to recreate all images it broke the site after which I had to install the site from a backup. The fact that there is an admin notice saying to backup the whole site before doing that only means that this is a common issue.

All in all I had very bad experience with the plugin and I don't recommend it to anyone.

Only problems

reSmush.it is the FREE image compressor and optimizer plugin - use it to optimize your images and improve the SEO and performance of your website.

ihorsl

WordPress Opti MozJpeg Guetzli WebP – is the FREE plugin for high quality image optimization in WordPress website. It was created to meet latest requirements of Google Pagespeed Insights. Google will “like” all your images after using this plugin, and you will expend $0 for that.
This plugin uses flowing image encoders: Mozilla MozJpeg, Google Guetzli and Google WebP. But don’t worry. There is no necessity to install them into your hosting. The plugin has built-in ssh client. It can access encoders remotely via ssh tunnel.
Plugin’s author created a virtual machine for Oracle VirtualBox. It contains Linux, ssh server and Mozilla MozJpeg, Google Guetzli and Google WebP. Simply run this virtual machine in your computer, establish ssh connection between the plugin and the virtual machine and optimize your images for free without any limitations.
Of course the plugin can use locally installed encoders too.
The plugin can create webp duplicates for all your images and serve them to webp compatible browsers. Lately Google Pagespeed changed the rules of the game. It wants now all images to be smaller then webp with quality 75 + 10%. And this plugin can do it for you.
The plugin can convert non alpha png images into jpeg. Automatically generates thumbnails and cleans not used thumbnail files.
All your images will be backed up before changing. You can run batch optimization many times, experiment with settings. And every time original images will be used as source. No quality degradation.
There is also the ability “Revert everything”. It can bring back the initial state of your images. All your images will be the same, as they were before this plugin use.
Please read <a href="http://ihorsl.com/en/wordpress-opti-mozjpeg-guetzli-webp/brief-man/" rel="nofollow ugc">this brief manual</a>, before using the plugin.
The virtual machine with encoders is <a href="http://ihorsl.com/redirect.php?t=wpmjgu-vm" rel="nofollow ugc">here</a>
If you have difficulties with use of the virtual machine in your computer, you may try the plugin author’s free online server. <a href="http://ihorsl.com/en/wordpress-opti-mozjpeg-guetzli-webp/free-server/" rel="nofollow ugc">Click here</a> to read more.

Opti MozJpeg Guetzli WebP

A bit complicated but it does what it said. The best images optimization so far.

No more next-gen formats warning

I did not test it yet, but the sole idea and effort brought into this requires 5 stars.

Great idea

WordPress Opti MozJpeg Guetzli WebP - is the FREE plugin for high quality image optimization in WordPress website. It was created to meet latest requi …

reSmush.it : The original free image compressor and optimizer plugin vs Opti MozJpeg Guetzli WebP