How to rename uploaded files in ImageUploader 4.0 when using the Concurrent upload process

<%@ Page Language="VB" AutoEventWireup="false" ValidateRequest="false" %>
<script runat="server">
'This variable specifies relative path to the folder, where the gallery 
'with uploaded files is located.
Private galleryPath As String = "../Gallery/"

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    'Get total number of uploaded files (all files are uploaded in a single package).
    Dim fileCount As integer = Int32.Parse(Request.Form("FileCount"))

    'Iterate through uploaded data and save the original file and thumbnail
    For I As Integer = 1 To fileCount
        'Get source file and save it to disk.
        Dim sourceFile As HttpPostedFile = Request.Files("SourceFile_" & I)
        Dim fileName As String = System.IO.Path.GetFileName(sourceFile.FileName)
        sourceFile.SaveAs(Server.MapPath(galleryPath & fileName))

        'Get first thumbnail (the single thumbnail in this code sample) and save it to disk.
        Dim thumbnail1File As HttpPostedFile = Request.Files("Thumbnail1_" & I)
        [i][b]thumbnail1File.SaveAs(Server.MapPath(galleryPath & "Thumbnails/" & fileName & ".jpg")) [/i][/b][b]//File was renamed with .jpg[/b]
    Next
End Sub
</script>

Dim intFileCount As Integer = CInt(Request.Form("PackageCount"))           

For I = 1 To intFileCount
    Dim StrFileName As String = Path.GetFileName(SourceFile.FileName) & "-" & I & ".jpg"
Next