Get width and height of Image in Unity 4.6

How can I get the width and height of an Image (or Button etc) in C# code in Unity 4.6?

Specifically, I am instantiating a prefab into a GameObject, and then want to access the width/height from that instance.

GameObject mynewcard = (GameObject)Instantiate(card); // where card is the prefab assigned in the editor to a public member variable.
mynewcard.size.width // nahh
mynewcard.width // no...

If your card is a prefab that has a RectTransform component. You can get the width/height using RectTransform.rect.

To get the RectTransform: (multiple options)

simply cast the transform to RectTransorm,

GameObject mynewcard = (GameObject)Instantiate(card);
RectTransform rt = (RectTransform)mynewcard.transform;

call GetComponent

GameObject mynewcard = (GameObject)Instantiate(card);
RectTransform rt = mynewcard.GetComponent<RectTransform>();

or get the RectTransform from the Image itself.

Image mynewcard = (Image)Instantiate(card); // Don't forget 'using UnityEngine.UI' and card must have a image Component ;)
RectTransform rt = mynewcard.rectTransform;

Then get the width/height

float width = rt.rect.width;
float height = rt.rect.height;

(Unity 4.6.0f2)