var imageRect = image.GetComponent<RectTransform>();
imageRect.anchorMin = Vector2.zero;
imageRect.anchorMax = Vector2.one;
imageRect.anchoredPosition = Vector2.zero;
imageRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Horizontal,Screen.width);
imageRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical,Screen.height);