There are several online tools and apps that use AI algorithms to analyze a photograph and detect a persons face shape. Here are some options:

• Face Shape Detector: This online tool allows you to upload a photograph and click on the "Detect Now" button to get your face shape. The tool also provides suggestions for glasses and hairstyles that will fit your face shape.

• Perfect Corp: This app analyzes facial features from a photo or selfie to determine the shape of a persons face. It can also analyze other features such as eyes and lips.

• Yesglasses: This website offers a face recognition tool that can help determine your face shape. It also provides recommendations for glasses that will fit your face shape.

• FaceShape app: This app uses advanced AI algorithms to analyze a single photograph and detect facial features such as face shape, face length, and jaw type.

Its important to note that while these tools can be helpful, they may not be 100% accurate. Additionally, there are six basic face shapes that are generally accepted: oval, round, square, heart, diamond, and oblong.