A CDN (Content Delivery Network) is a global network of servers that cache your files and serve each visitor from the location nearest to them — so images arrive faster.
What an image CDN adds
Beyond plain caching, an image CDN can transform images on the fly: resize, compress, and convert to modern formats like WebP/AVIF per device. The visitor always gets a right-sized, well-compressed file.
Do you need one?
- Small site / blog: probably not — just ship well-compressed images and use lazy loading.
- Lots of traffic or images: an image CDN pays off in speed and bandwidth.
The cheap-and-simple route
Before reaching for a CDN, get the basics right: correct dimensions, compressed files, and browser caching. That alone fixes most slow-image problems.