Error when sending an image to Gemini

[HamzaFarhan]

Initial Checks

• I confirm that I'm using the latest version of Pydantic AI

Description

Getting this error with Gemini but not with GPT

Example Code

from pydantic_ai import Agent, ImageUrl

agent = Agent(model="google-gla:gemini-2.0-flash-exp")
result = await agent.run(["What company is this logo from?", ImageUrl(url="https://goo.gle/instrument-img")])

"""
UnexpectedModelBehavior: Unexpected response from gemini 400, body:
{
  "error": {
    "code": 400,
    "message": "Invalid JSON payload received. Unknown name \"data\" at 'contents[0].parts[1]': Cannot find field.\nInvalid JSON payload received. Unknown name \"mimeType\" at 'contents[0].parts[1]': Cannot find field.",
    "status": "INVALID_ARGUMENT",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.BadRequest",
        "fieldViolations": [
          {
            "field": "contents[0].parts[1]",
            "description": "Invalid JSON payload received. Unknown name \"data\" at 'contents[0].parts[1]': Cannot find field."
          },
          {
            "field": "contents[0].parts[1]",
            "description": "Invalid JSON payload received. Unknown name \"mimeType\" at 'contents[0].parts[1]': Cannot find field."
          }
        ]
      }
    ]
  }
}
"""

Python, Pydantic AI & LLM client version

Python 3.12.7
Pydantic AI 0.0.26