optimising

WP TinyPNG utilise the TinyPNG API to compress your PNG images neatly within WordPress.

WP TinyPNG

WP TinyPNG utilise the TinyPNG API to compress your PNG images neatly within WordPress.

alpipego

Instead of creating image sizes on upload, this plugin only creates them when requested.
Normally after activating a new theme or plugin that adds new image sizes, you will have to use a tool like <a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a> to create the newly registered image sizes. Depending on the size of the media library and the “power” of your server, this might take a while or even take several tries to process all your images; and in the end, you don’t even know if you’ll need all of the resized images.
This plugin takes care of the resizing dynamically and creates the requested size the moment it is first requested—and only when it is requested.
<h4>Support</h4>
For users: Please use the support forums on <a href="https://wordpress.org/support/plugin/resizefly" rel="ugc">wordpress.org</a> 
For developers: Head over to the <a href="https://github.com/alpipego/resizefly/" rel="nofollow ugc">Github repository</a> 
For everything else, find me on <a href="https://twitter.com/alpipego" rel="nofollow ugc">twitter</a> or on slack

ResizeFly

Nice idea!

Dynamically resize your WordPress images on the fly. Upload them once and don't worry about missing or new image sizes.

WP TinyPNG vs ResizeFly