Content Delivery Bandwidth

Content delivery bandwidth is the amount of data that is served to your users. Any image that is requested will add to your total bandwidth charge.

Content Delivery Network (CDN)

A Content Delivery Network (CDN) is a network of globally-distributed computers designed to accelerate the transfer of content (e.g. text, images, video) to your end users. By storing copies of your content closer to where your end users will access it, a content delivery network can dramatically improve the performance of your website or application.

imgix serves all of your images through a content delivery network to ensure that they load as quickly as possible across the entire globe.

Derivative Image

A derivative image is the result created when imgix applies renders and processes a master image, which we deliver upon request. Once a derivative image is requested and rendered, any subsequent identical requests will be fulfilled from the CDN, dramatically improving performance. imgix aggressively caches images in our CDN once they’ve been rendered, in order to provide the best delivery performance possible.

Image Fetch

An image fetch is the action taken by imgix to retrieve a master image from your image Source.

Fetching a master image from an image source is the most time-consuming task in a request. Therefore, imgix aggressively caches images that are fetched so that fetches only occur when absolutely necessary, making all subsequent requests significantly faster.

Master Image

A master image is your original full-size image, stored at your storage provider (or Origin).

Master images are owned and controlled by you. You configure Sources within imgix to connect imgix to your master images. Once connected via an image Source, imgix will fetch master images from your storage provider on demand for rendering whenever necessary.


An Origin is the publicly-addressable Internet location where your master images are stored. This could be Amazon S3 or another host.


A Source is the set of configuration options that connect imgix to your master images at the Origin. It tells us where the images are, what imgix domain you want to use to request them, and other options related to caching and security. See the Creating Sources guide for more information on how to set up your Source.