garden_client/Assets/Script/Extension/ExtensionImage.cs

using UnityEngine;
using UnityEngine.UI;

using System.Collections;

public static class ExtensionImage
{
    public static void Resize(this Image image, float ratioX, float ratioY)
    {
        Vector2 newSize = image.sprite.rect.size;

        newSize.x *= ratioX;
        newSize.y *= ratioY;

        image.rectTransform.sizeDelta = newSize;
    }
}