Even his one-liners can only be considered that for very large values of one...

Here's a true on-line version, including error checking, but I don't know why anyone would bother with such code (unless the name's snb, but then there'd be no error-checking):
Sub InsertImage()
If UBound(Split(CreateObject("wscript.shell").Exec("Cmd /c Dir ""C:\Users\%UserName%\Documents\Attachments\" & Split(Trim(ActiveDocument.Paragraphs.First.Range.Text), " ")(0) & ".jpg"" /B/S").StdOut.ReadAll, vbCrLf)) > 0 Then Selection.InlineShapes.AddPicture Split(CreateObject("wscript.shell").Exec("Cmd /c Dir ""C:\Users\%UserName%\Documents\Attachments\" & Split(Trim(ActiveDocument.Paragraphs.First.Range.Text), " ")(0) & ".jpg"" /B/S").StdOut.ReadAll, vbCrLf)(0), False, True
End Sub
PS: The line's so long the code tags here can't handle it properly...