You could do that with a macro like:
Code:
Sub Demo()
Application.ScreenUpdating = False
Dim i As Long
With ActiveDocument.Range
With .Find
.ClearFormatting
.Replacement.ClearFormatting
.Text = "<img id=" & Chr(34) & "img001" & Chr(34) & " src=" & Chr(34) & Chr(34) & "/>"
.Replacement.Text = ""
.Forward = True
.Wrap = wdFindStop
.Format = False
.MatchCase = False
.MatchWholeWord = False
.MatchWildcards = False
.MatchSoundsLike = False
.MatchAllWordForms = False
.Execute
End With
Do While .Find.Found
i = i + 1
.Start = .Start + 12
.End = .Start + 3
.Text = Format(i, "000")
.Collapse wdCollapseEnd
.Find.Execute
Loop
End With
Application.ScreenUpdating = True
MsgBox i & " tags found."
End Sub