The CWG website elucidates what this means:
The CWG Seal of Approval is a kind of “gatekeeping” device for Catholic bookstore owners and readers. Simply put, it’s an endorsement that the book supports Catholic beliefs and values. We began the SoA after discussions with Catholic bookstore owners who said they often did not have time to fully evaluate books—and often didn’t stock books that came from unknown writers or smaller presses.
The SoA is not a critique of a work, but rather an assurance of its Catholicity--that neither the work nor its author go against the Mageristerial authority of the Catholic Church. In other words, we evaluate for faithfulness, not for writing style or quality.
The CWG is a great group of Catholic creative folks whose expertise and knowledge I very much respect. If you're a writer (fiction, non-fiction, poetry), an artist or illustrator, or an editor or publisher and you are NOT a member yet, what's stopping you? Go check out their website and join in the fun!
In His Image, please do -- it's gotten very good comments from those readers who have been gracious enough to share their thoughts with me ....