# Image Processor settings [Image Processor](/en/documentation/platform/applications/#image-processor) is a module of [Applications](/en/documentation/platform/applications/), turned on for one application at a time. With the module on, a request for an image can carry an `ims` query string that describes a transformation. Azion returns a derived image built from the source image on the origin. This page carries the field, the flag, and the interface that sets each one, plus the behaviors, cache fields, headers, and datasets the module reaches. --- ## Module activation Five interfaces set the same switch, and the switch belongs to the application: one application can carry the module while another does not. | Interface | Where you set it | Field or flag | | --------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------- | | Azion Console | The **Default Modules** group of the **Modules** section, on the **Main Settings** tab of an application | The **Image Processor** toggle, with the helper text "Enable dynamic image editing options." | | Azion API v4 | `PATCH /v4/workspace/applications/` | `modules.image_processor.enabled` | | Azion API v3 | `PATCH https://api.azionapi.net/edge_applications/` | `image_optimization` | | [Azion CLI](/en/documentation/devtools/cli/) | `azion create application` and `azion update application` | `--image-processor` | | [`azion.config.js`](/en/documentation/devtools/cli/azion-config-js/) and [Azion Lib](/en/documentation/devtools/azion-lib/) | The application object | `imageProcessorEnabled` | `modules.image_processor.enabled` and `imageProcessorEnabled` are booleans, and `imageProcessorEnabled` defaults to `false`. The Azion CLI flag takes a string: `--image-processor true`. In Azion Console, the toggle is saved with **Save**. API v4 carries the switch in the `modules` object of the application: ```json { "modules": { "image_processor": { "enabled": true } } } ``` The same `modules` object carries `application_accelerator`, `cache`, and `functions`, each with its own `enabled` boolean. API v3 names the switch `image_optimization` and takes it at the top level of the body. --- ## Rules Engine behaviors Three [Rules Engine](/en/documentation/platform/applications/rules-engine/) behaviors build the rule that processes an image. **Optimize Images** requires the Image Processor module on the application that runs the rule. | Behavior | Phase | API type | What it does | | ---------------------- | ----------------- | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Optimize Images** | **Request Phase** | `optimize_images` | Enables Image Processor for the matched request. It takes no attributes. | | **Set Cache Policy** | **Request Phase** | `set_cache_policy` | Applies a cache setting to the matched request. `attributes.value` carries the id of the cache setting, and Azion Console names it in a second dropdown. | | **Add Request Header** | **Request Phase** | `add_request_header` | Adds a header to the request. `attributes.value` takes the form `Field: value`, such as `Accept: image/webp` or `Accept: image/avif`, which is what a conversion to those formats requires. | A criterion of the same rule carries `variable`, `operator`, `conditional`, and `argument`. A rule that matches image requests reads `${request_uri}` or `${uri}` with the `matches` operator, against an argument such as `\.(jpg|jpeg|gif|bmp|png|ico|webp|avif)`. --- ## Cache variation A derived image is cached under its own key. The cache key includes the `ims` query string, and a variation with a converted format carries the file format after the separator, as in `httpsstatic.yourdomain.com/static/images/image_1.jpg?ims=880x@@webp`. Varying the cache on a query string is an [Application Accelerator](/en/documentation/platform/applications/#application-accelerator) field: `cache_vary_by_querystring` lives under `modules.application_accelerator` in a cache setting. Varying the cache on `ims` therefore requires that module. Processing an image does not require it. | Field | Console control | What it sets | | ---------------------------------------- | --------------- | ------------------------------------------------------------------------------------------------------------------- | | `cache_vary_by_querystring.behavior` | **Behavior** | How the cache handles query string parameters. The dropdown offers *Allowlist*, *Denylist*, *Ignore*, and *All*. | | `cache_vary_by_querystring.fields` | **Fields** | The query string parameters considered for cache variation, one per line. A cache setting for images carries `ims`. | | `cache_vary_by_querystring.sort_enabled` | **Sort** | Whether query string parameters are sorted, so that cache behavior does not depend on the order they arrive in. | In Azion Console, the three controls sit in the **Cache vary by Query String** panel of the **Application Accelerator** section of a cache setting. For the rest of the fields a cache setting carries, including the maximum age of the cached object, refer to [Cache Settings](/en/documentation/platform/applications/cache/cache-settings/). For the other fields the module unlocks, refer to [Application Accelerator settings](/en/documentation/platform/applications/application-accelerator/settings/). --- ## Response headers Azion returns two headers on the response to a request that carries an `ims` query string. | Header | What it carries | | ----------------------- | -------------------------------------------------------------------------------------------- | | `x-ims` | Whether Image Processor handled the response. A processed response carries `x-ims: Enabled`. | | `x-original-image-size` | The size in bytes of the source image, before the transformation. | --- ## Usage and event data Azion reports Image Processor activity on six surfaces: two in Real-Time Metrics, two in Real-Time Events, and two in GraphQL. | Surface | What it carries | | --------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ | | The **Image Processor** tab of [Real-Time Metrics](/en/documentation/platform/real-time-metrics/) | Metrics for the requests made to the images processed through Image Processor in your account, as Total Requests and Total Requests per Second charts. | | The **Bandwidth Saving** graph of Real-Time Metrics, under Applications | The traffic the account saved. | | The **Image Processor** dataset of [Real-Time Events](/en/documentation/platform/real-time-events/) | The event records of requests made to applications using Image Processor. The dataset requires the module. | | The **Proxy Upstream** field of Real-Time Events | `ims_http`, the value the field reads when the Tiered Cache origin is Image Processor. | | The consumption dataset of [GraphQL](/en/documentation/devtools/graphql/gql-consumption-fields/) | `productId` `1441110021` and the metric `images_processed`, the total number of images processed by Image Processor. | | The [metrics datasets](/en/documentation/devtools/graphql/gql-real-time-metrics-fields/) of GraphQL | The `imageProcessedMetrics` dataset and its fields. | The data is available for up to 24 months. To build the consumption query and read its response, refer to [Query usage data from Image Processor](/en/documentation/guides/platform/observability/query-image-processor-usage-data-with-graphql/). --- ## WASM Image Processor library WASM Image Processor is a WebAssembly library that processes images inside a [Functions](/en/documentation/platform/functions/) function. It carries `loadImage`, `resize`, `getImageResponse`, and `clean`, and it writes `webp`, `jpeg`, and `png`. It is a different product surface from the Image Processor module, and no field on this page configures it. For more information, refer to [WASM Image Processor](/en/documentation/devtools/azion-lib/wasm-image-processor/). --- ## Related resources - [Image Processor quickstart](/en/documentation/platform/applications/image-processor/quickstart.md): Turn the module on and request a transformed image for the first time. - [Image delivery](/en/documentation/platform/applications/image-processor/image-delivery.md): The path a request for a derived image takes, and where the transformation happens. - [Image Processor URL parameters](/en/documentation/platform/applications/image-processor/url-parameters.md): The grammar of the `ims` query string these settings switch on. - [Process images](/en/documentation/guides/application-performance/delivery-optimization/process-images.md): The steps that turn the module on and build the rule, interface by interface.