The PictureController will expose a method SetFrame() that takes a frame game object as a parameter. It will delete the existing frame in the FramedImage and spawn (add) the selected one instead. Make the following additions to the PictureController.cs script.

At the top of the class, add a variable for the frame spawn:

File: PictureController.cs
    private Renderer imageRenderer; 

Initialize this in Start(). We already have a reference to the framedImage, so it's safe to just find its child Image:

    void Start() { 
        ... 
        Transform image = framedImage.Find("Image"); 
        imageRenderer = image.gameObject.GetComponent<Renderer>(); 

Now we can write the public function SetFrame as follows:

    public void SetFrame(GameObject frameGameObject) { 
        GameObject currentFrame = GetCurrentFrame(); 
        if (currentFrame != null) 
            Destroy(currentFrame); 
 
        GameObject newFrame = Instantiate(frameGameObject, frameSpawn); 
        newFrame.transform.localPosition = Vector3.zero; 
        newFrame.transform.localEulerAngles = Vector3.zero; 
        newFrame.transform.localScale = Vector3.one; 
    } 
 
    private GameObject GetCurrentFrame() { 
        Transform currentFrame = frameSpawn.GetChild(0); 
        if (currentFrame != null) { 
            return currentFrame.gameObject; 
        } 
        return null; 
    } 

We also added a helper function to get the current frame as the first (and only) child of FrameSpawn. SetFrame gets the current frame and deletes it. Then it creates a new frame based on the one selected from the menu and resets its transform.

The next step is to build the menu itself.