# ImageBlockStart
<a name="API_runtime_ImageBlockStart"></a>

The initial event in a streaming image block that indicates the start of image content.

## Contents
<a name="API_runtime_ImageBlockStart_Contents"></a>

 ** format **   <a name="bedrock-Type-runtime_ImageBlockStart-format"></a>
The format of the image data that will be streamed in subsequent delta events.  
Type: String  
Valid Values: `png | jpeg | gif | webp`   
Required: Yes

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/bedrock-runtime-2023-09-30/ImageBlockStart) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/bedrock-runtime-2023-09-30/ImageBlockStart) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/bedrock-runtime-2023-09-30/ImageBlockStart)