The answer to this question could be put in a full blog, but it’s a Content Delivery Network.
In short, it’s a server, separately from your hosting website server, that stores and delivers your images (and some other files) to your users’ browsers. It can be much faster than your hosting server, but it also provides another feature.
Cookie Free Domains
Within an SEO scan is a test called ‘Y-Slow’. Within this scan it shows what “Cookie Free Domains’ you are using, or rather, NOT using. The higher the score, the better. A good CDN will load your images from a Cookie Free Domain. A bad CDN won’t, and thus cause your Y-Slow score to be low – and not good.
There are many CDN providers out there. A few are free, but not so professional. We use a Pro Tool on our sites where the clients has a WP Support package with us. This improves the SEO results, and the overall Page Score.
Could we install it on your website? Most likely yes, if you are using WordPress it’s very easy to do.