UmbracoHelper.cshtml

@using umbraco.MacroEngines;
@using System.Xml;

@functions {
    public static string GetMediaCropperUrl(object crops, string cropName)
    {
        string cropUrl = string.Empty;

		if (crops.GetType() == typeof(DynamicXml))
		{
			DynamicXml cropsXml = (DynamicXml)crops;

			XmlDocument xmlDocument = new XmlDocument();
			xmlDocument.LoadXml(cropsXml.BaseElement.ToString());
			XmlNode cropNode = xmlDocument.SelectSingleNode("descendant::crops/crop[@name='" + cropName + "']");

			if (cropNode != null)
			{
				cropUrl = cropNode.Attributes.GetNamedItem("url").InnerText;
			}
		}

        return cropUrl;
    }
}