uGUIのLayoutElementの値が、アタッチしたオブジェクトと子オブジェクトの関係性（子のAnchorをBottomにしてたりする）によってレイアウトが安定しない件を解消するスクリプト。

UISizeFitter.cs

using UnityEngine;
using UnityEngine.UI;
# if UNITY_EDITOR
using UnityEditor;
[CustomEditor( typeof( UISizeFitter ) )]
public class UISizeFitterInspector : Editor{
	public override void OnInspectorGUI()
	{
		DrawDefaultInspector();
		var script = target as UISizeFitter;
        
        if( GUILayout.Button("Fit") ){
            script.Fit();
        }
        
	}
}
# endif

// namespace jigaX{
[RequireComponent( typeof( LayoutElement) )]
public class UISizeFitter : MonoBehaviour {
    RectTransform rectTransform;
    LayoutElement layoutElement;
    Image image;
	void Awake(){
	   this.layoutElement = GetComponent<LayoutElement>();
       this.rectTransform = GetComponent<RectTransform>();
       this.image = GetComponent<Image>();
	}

	// Use this for initialization
	void Start () {
	   this.Fit();	   
	}
	// Update is called once per frame
	void Update () {
	}
    public void Fit(){
        var imageRect = this.image.sprite.rect;
        var ratio = imageRect.height / imageRect.width;
        var rect = this.rectTransform.rect;
        Debug.Log(imageRect,this);
        this.layoutElement.preferredHeight = rect.width * ratio; 
    }
}

// } // namespace