Unique identifier of the specified item in the upload list.
value = getImageUploader("ImageUploaderID").getUploadFileGuid(Index);
A positive integer which specifies an index of the upload list item (i.e. the upload file). An index is 1-based. In other words valid value is in range [1, UploadFileCount].
A string value containing GUID that identifies this item.
Use this property to associate an upload item with a standalone Thumbnail control. Just assign it to the Thumbnail.Guid property.