使用ElementLayer加载world file

【解决办法】：
根据测试和美国工程师的确认，ElmentLayer只是用来加载rectangle的图片，故旋转参数无效。但是也有变通方式，变通方式如下：


As we discussed before adding georeferenced images to a Silverlight application is not a supported operation. However I was able to find a way to add these images to the map using the ElementLayer class. My testing has confirmed it is not possible to add a rotated image to an ElementLayer. My recommendation is to rotate all of the images in ArcMap using the georeferencing toolbar. You will then need to update the georeferencing and export the image. The resulting image will look like the attached image and you will be able to display it in my sample code correctly. I am going to go ahead and mark this case as closed.