imgix is a really great image delivery and manipulation tool. It has an extensive and powerful API which drives processing of the image before delivery. And it caches images by delivering them through a CDN (content delivery network). imgix does not have a free tier, but I find it to be absolutely worth the cost.
Typically we see imgix used most with cloud storage providers like s3, but it can actually deliver images from any web folder, which essentially means any set of images with a predictable and consistent URL structure.
And when you retrieve assets from Contentful, you'll notice they have just that – a consistent URL structure. It looks like this:
Notice that each image is accessible behind its
space_id. This is the crux of how we get imgix to play well with Contentful without letting others abuse your imgix account. The
images.ctfassets.net domain from which the images are delivered are shared among all Contentful accounts. That means if you added
https://images.ctfassets.net as your source, anyone could use your imgix account to deliver their Contentful assets.
So, the way you set up imgix just for your Contentful space is to configure a source to use a web folder with the following URL structure:
Once you have that in place any image that was available from
https://images.ctfassets.net/<space_id>/<image_id>/<image_token>/<filename> is now available from
https://<imgix_domain>/<image_id>/<image_token>/<filename>. Note the difference – replace
images.ctfassets.net/<space_id> with your imgix domain and – voila! – you are serving Contentful assets from imgix and now have the power of the imgix transformations.
One major caveat before we depart from this thrilling monologue. Contentful has an Images API, which uses similar URL parameters to manipulate and deliver images to you.
If you aren't already paying for imgix and if you don't need some of the more fine-grained controls offered by imgix (i.e. if you only need some basic cropping tools), then I'd recommend using the Contentful Images API since you're already paying for it. Contentful's assets are also delivered via a CDN, which means you still have the benefit of caching and quick delivery from all over the world.
In other words, this was an example of how you could enable imgix to serve your Contentful assets, not that you should. It, no doubt, complicates your asset delivery, so if you can stick with using the Contentful Images API, do that instead.