Hi,

once you have saved a media item and want to present it to the front end, then using the UmbracoHelper should work, (so in a partial or macro)

var media = Umbraco.TypedMedia(xxx) 
var imgPath = media.GetPropertyValue("umbracoFile") 

should return the virtual path (like "/media/1092/image.gif")

however if you want to say in the back office with the services, you can access it via GetValue so

var item = Services.MediaService.GetById(xxx);
var filePath = item.GetValue<string>("umbracoFile");

this will still be the virtual path, so you might need to map it. in the umbraco back office IOHelper can do that.

string fullpath = IOHelper.MapPath(string.Format("~{0}", filePath));

*All of the above assumes you are not using the image cropper, - as that stores JSON in the umbracoFile property.