mcp-image-handling-when-a-fastmcp-tool-returns-an-image-object-using--a188af47

THEN Upgrade to FastMCP 2.0 (from gofastmcp.com) which correctly handles image returns. Alternatively, manually encode the image as a data URI with proper MIME type in the tool's response instead of relying on the SDK's Image type.

from fastmcp import FastMCP, Image
mcp = FastMCP('MyApp')
@mcp.tool()
def create_thumbnail(image_path: str) -> Image:
    # Using FastMCP 2.0 resolves client-side rendering issues
    img = PIL.Image.open(image_path)
    img.thumbnail((100, 100))
    return Image(data=img.tobytes(), format='png')