Without knowing how the images are inserted it is something of a guess, but the following will insert the date in the required format after each image.
Code:
Sub Macro1()
'Graham Mayor - http://www.gmayor.com - Last updated - 02 Nov 2017
Dim iShp As Integer
Dim dStartDate As Date
Dim oRng As Range
Dim strDate As String
dStartDate = "01/01/2018"
For iShp = 1 To ActiveDocument.InlineShapes.Count
strDate = Format((dStartDate + iShp), "mmmm d") & _
DateOrdinal(Format((dStartDate + iShp), "d")) & _
Format((dStartDate + iShp), " yyyy")
Set oRng = ActiveDocument.InlineShapes(iShp).Range
oRng.Collapse 0
oRng.Text = vbCr & strDate & vbCr
Set oRng = oRng.Paragraphs(2).Range
oRng.Font.Size = 24
oRng.ParagraphFormat.Alignment = wdAlignParagraphCenter
Next iShp
lbl_Exit:
Set oRng = Nothing
Exit Sub
End Sub