---
title: About Fastly Image Optimizer
summary: null
url: >-
  https://www.fastly.com/documentation/guides/full-site-delivery/image-optimization/about-fastly-image-optimizer
---


Fastly's [Image Optimizer](https://docs.fastly.com/products/image-optimizer) (Fastly IO) is an image optimization service that manipulates and transforms your images in real time and caches optimized versions of them. When an image is requested from your origin server, Fastly IO can perform one or more transformation tasks before serving and caching the optimized version. For example, you can [resize](/reference/io/width/), adjust [quality](/reference/io/quality/), [crop](/reference/io/crop/) and [trim](/reference/io/trim/), serve [responsive images](/reference/io/#using-optimized-images-and-videos-in-html), and [more](/reference/io/).

> **WARNING:** Only send image content through Fastly IO. Non-image content can't be optimized using it, but will still be counted and charged as an image optimization request, which may cost you more.

## Prerequisites and considerations

> **NOTE:** To use Image Optimizer with Compute as part of Fastly's Beta program, [contact support](https://support.fastly.com).

Before you begin using Fastly IO, keep the following in mind:


* Fastly's [Image Optimizer](https://docs.fastly.com/products/image-optimizer) is disabled by default. Anyone assigned the role of [superuser](/guides/account-info/user-and-account-management/about-user-roles-and-permissions) can enable Image Optimizer from the Service configuration tab or on the [Products page](/guides/account-info/billing/managing-product-purchases-and-trials). To use Image Optimizer with Compute as part of Fastly's Beta program, [contact support](https://support.fastly.com/).
* Image Optimizer is available on the Compute platform through our SDKs as part of Fastly's [Beta program](https://docs.fastly.com/products/fastly-product-lifecycle#beta). Any request sent to Image Optimizer, including through the SDK, counts as a [billable image request](https://docs.fastly.com/products/image-optimizer#billing) for the Image Optimizer product.
* Services that use image optimization require shielding. When enabling Image Optimizer on a Fastly VCL service, select a [fallback location](/guides/concepts/shielding/#choosing-a-shield-location) that's as geographically close to your image's origin as possible. This will help determine the optimal shield location for any requests for Image Optimizer transformations that need to go back to an origin that doesn't have shielding enabled. Check out our [shielding guide](/guides/concepts/shielding/) to learn more about how shielding works.
* When using Image Optimizer on Compute as part of our Beta program, shielding is configured automatically when you select a region.
* Some features, like AVIF and JPEGXL [encoding format](/reference/io/format/), may require an account upgrade. Existing customers can contact [sales@fastly.com](mailto:sales@fastly.com) for more information on pricing, features, and account upgrades.


## What's next

[Follow our guide](/guides/full-site-delivery/image-optimization/using-fastly-image-optimizer) to learn how to enable and start using Fastly IO.

> **NOTE:** <Partial name='cloud-security' inline />

## Related content

* [Using Fastly Image Optimizer](/guides/full-site-delivery/image-optimization/using-fastly-image-optimizer)
* [Image Optimizer reference documentation](/reference/io/)
* [Image optimization debugging](/reference/io/#testing-and-debugging)
* [Image Optimizer API documentation](/reference/api/products/image_optimizer/)