[FEATURE] Model Providers - Always Base64 Encode Images

[pgrayy]

Problem Statement

Currently, in the OpenAI model provider, we accept image data as both raw and base64 encoded bytes. For consistency with the other providers and also general convenience, we should only accept raw bytes and base64 encode on behalf of customers. The check for both adds a slight performance overhead.

Proposed Solution

• Log a warning when customers base64 encode the image data themselves when using the OpenAI provider.
• Move to only accepting raw bytes in the 0.3.0 release.

Use Case

Image generation

Alternatives Solutions

No response

Additional Context

No response