Invalid base64 format detected in image_url. Please ensure the input is correctly encoded in base64 format.

The "400 Invalid base64 image_url" error in the OpenAI API can be triggered by several reasons:

Incorrect Base64 Encoding

The base64 encoded string may not be correctly formatted or may contain errors. For instance, the string might be missing the appropriate prefix (data:image/jpeg;base64, or data:image/png;base64,) or could have invalid characters.

Invalid Payload Structure

The payload structure, particularly the 'content' keys, might be incorrectly defined. The content should be an object rather than a string, and the image_url should be properly nested within this structure.

Model Specific Requirements

The gpt-4-vision-preview model requires the image content to be a Base64 encoded string, and using a URL instead can result in this error. Even if the base64 string is valid, the model's specific requirements must be met.

Network or API Configuration Issues

There could be issues with the API request configuration, such as incorrect headers or an incorrectly set base URL, which can lead to a "Bad Request" error.