Image Optimization Plugins for WordPress
ShortPixel Image Optimizer
I described ShortPixel in great detail above. From reading the description page in the WordPress plugin repository, I learn that their tool will optimize PDF files as well. They offer a free plan as well as paid plans. All plans have the same feature set, it’s just the number of images that can be processed that changes.
As of this writing, ShortPixel boasts 4.6 out of 5 stars, and has more than 20,000 active installs.
Kraken Image Optimizer
You can try the Kraken WordPress plugin for free. However, in order to use it beyond the 50 MB testing quota, you will be required to upgrade to a paid plan starting at $5 per month. Visit their website to see the full feature set.
With this plugin, I like that you get the choice on which EXIF data you would like to retain, if any. By default, none are selected.
TinyPNG: Compress JPEG & PNG images
Not a feature I realized that I would appreciate until reading about it, but TinyPNG offers you the ability to choose which thumbnails you want to optimize. Since your theme, and possibly other plugins, register several thumbnails with WordPress, it could be taking a lot of “credits” (or however you are charged by a given image optimization plugin), unnecessarily if you don’t need all the thumbnails. But, how do you decide which ones to optimize? I don’t know, but I like having the option of choosing which thumbnails that I want to auto-process either way.
TinyPNG is a utility that some other tools use within their proprietary approach to image optimization. That’s cool.
This tool has been around for quite awhile, and has more than 40,000 active installs of the WordPress plugin..