Pixpie - Optimize your images and speed up your site on WordPress
speedtest-cli - Test your download speed using SpeedTest on the command-line
Website Image Speed Test - Beautiful & easy free analysis of the images on your page
Global Website Speed Test - Test website load speed from 18 cities, including 3 in China
Pixabay Images 3.0 for WordPress - Search and insert images directly within WordPress
Speedtest by Ookla - Measure your ISP's performance in a click