---
title: "AnthropicImageBlockParam"
---

## Fields

| Field                                                                                                                                                                                                                                                                                                                                                                                      | Type                                                                                                                                                                                                                                                                                                                                                                                       | Required                                                                                                                                                                                                                                                                                                                                                                                   | Description                                                                                                                                                                                                                                                                                                                                                                                | Example                                                                                                                                                                                                                                                                                                                                                                                    |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `cache_control`                                                                                                                                                                                                                                                                                                                                                                            | [Optional[components.AnthropicCacheControlDirective]](../components/anthropiccachecontroldirective.mdx)                                                                                                                                                                                                                                                                                     | :heavy_minus_sign:                                                                                                                                                                                                                                                                                                                                                                         | Enable automatic prompt caching. When set at the top level, the system automatically applies cache breakpoints to the last cacheable block in the request. When set on an individual content block, it marks an explicit cache breakpoint; block-level markers also work on OpenAI models that support explicit prompt caching — OpenRouter converts them to the provider's native format. | \{<br/>"type": "ephemeral"<br/>}                                                                                                                                                                                                                                                                                                                                                            |
| `source`                                                                                                                                                                                                                                                                                                                                                                                   | [components.AnthropicImageBlockParamSource](../components/anthropicimageblockparamsource.mdx)                                                                                                                                                                                                                                                                                               | :heavy_check_mark:                                                                                                                                                                                                                                                                                                                                                                         | N/A                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                            |
| `type`                                                                                                                                                                                                                                                                                                                                                                                     | [components.AnthropicImageBlockParamType](../components/anthropicimageblockparamtype.mdx)                                                                                                                                                                                                                                                                                                   | :heavy_check_mark:                                                                                                                                                                                                                                                                                                                                                                         | N/A                                                                                                                                                                                                                                                                                                                                                                                        |                                                                                                                                                                                                                                                                                                                                                                                            |