This add-on adds 'lazy loading images' to your forum with minimal impact.
This will have a positive effect on your PageSpeed score, especially for the mobile test.
Simply check the difference with and without this add-on.
Loading image lazy means your browser will only download images when...
Automatically optimize any image uploaded to your forum. Compress your photos to save storage space and bandwidth and improve your website's load time. (Currently requires Kraken, but will add support for more image optimization services soon.)