Try something like the code below, which hasnt been tested, and may need a little work - but should give you an idea on how to do what you need
Dim objDir As IO.Directory
Dim objFile As IO.File
Dim strFile As String
For Each strFile In objDir.GetFiles("c:\myfolder")
If Mid(strFile, Len(strFile) - 4) = "jpeg" Then
objFile.Copy(strFile, "c:\backup\" + Mid(strFile, _
strFile.LastIndexOf("\") + 1))
End If
Next