Hi,
You always need to change it, regardless what file you upload. The uploader only stores the files in a temporary folder and you have to move it to wherever you really want the files to be (and rename the file accordingly when you move it, by calling File.Move). The uploader frequently cleans up the temporary folder so if you don't move it, it will eventually be deleted by the uploader.
You can find out the original name of the file via this property:
http://www.essentialobjects.com/ViewDoc.aspx?t=EO.Web.AJAXPostedFile.ClientFileName.htmlThanks