v0.15.6

Documentation only. No code changes, no API changes.

Found by running v0.15.5 against the live API rather than a stub: generateImage() works, but the Gemini image models return image/jpeg by default, while every example wrote the bytes to output.png / image.png / edited.png. The bytes were correct, the filename was not, and anything dispatching on file extension would have been misled.

The MIME type is already returned on each image, so the examples now derive the extension from the response:

$extension = str_replace('image/', '', $image['mimeType']);
file_put_contents("output.{$extension}", base64_decode($image['data']));

Live verification of the v0.15.5 image path, six checks, all passing: image returned and decodable (image/jpeg, 1408x768), aspectRatio and imageSize honoured (2752x1536 for 16:9 at 2K), numberOfImages > 1 throwing rather than returning one image, generateImageToFile() writing a valid file, chat working on the default model, and effort mapping to a thinking level without error.