Works very good with Firefox Quantum. Extremely useful if you are on limited data and want to eliminate unnecessary images from consuming your data. It will load the images when disabled and page refreshed but will keep the same setting for subsequent tabs. Would be more useful if remembered the tab setting and even more if loads selected images.
All in all thanks for the effort of Christian Kuhl.

Works well. There's an option to auto-refresh the page when you switch on or off.

Great extension! It helped me to be more concentrated while reading. If there is something to say about this app, sometimes the alternate texts on images pop out from the image region and overlap other texts. So it would be better if it shows a simple place holder instead (like what you see on in Android Firefox if you block 'Show images' in 'Settings' > 'Advanced'> 'Data saver' ).