This pull request includes changes to the OpenAiImageOptions class and its corresponding test class to improve handling of width and height properties. The most important changes include updating the setWidth and setHeight methods to properly compute the size property only when both width and height are set, and updating the test cases to reflect these changes.

Improvements to width and height handling:

Test case updates:

Code cleanup:

Comment From: markpollack

thanks! merged in 95eb9fd6a350ef4e336b301ea0fd2d148e63dded