The behaviour is typically caused by the image and its caption being separate objects that lack any 'keep together' capacity.
The following macro embeds all Shapes & InlineShapes in a document in tables as InlineShapes with a row for Captions. Whatever positioning applied to the original Shape object will apply to the table also.
To have the caption row appear above the image, instead of below, change the Rows(1) references to Rows(2), change the Cell(1, 1) references to Cell(2, 1) and change the change the Cell(2, 1) references to Cell(1, 1).
Note that, due to the extra space taken up by the caption row, all except for the first of the document's pictures are liable to shift position.
Once the macro has run, you'll need to move your captions into the empty table cell; after that, they should reliably stay together.
Code:
Sub AddImageCaptionTables()
Dim iShp As InlineShape, Rng As Range, Tbl As Table
Dim i As Long, PicWdth As Single, PicHght As Single, VPos As Single
Dim HPos As Single, VRel As Long, HRel As Long, BShp As Boolean
With ActiveDocument
For i = 1 To .InlineShapes.Count
If .InlineShapes(i).Range.Information(wdWithInTable) = False Then
With .InlineShapes(i)
.LockAspectRatio = True
PicWdth = .Width
PicHght = .Height
Set Rng = .Range
End With
With Rng
If .Characters.Last.Next.Text = vbCr Then .Characters.Last.Next.Text = vbNullString
.InlineShapes(1).Range.Cut
End With
BShp = False: VRel = 0: HRel = 0: VPos = 0: HPos = 0
Call MakeImageTable(Rng, PicWdth, PicHght, BShp, VRel, HRel, VPos, HPos)
End If
Next
While .Shapes.Count > 0
BShp = True
With .Shapes(1)
.LockAspectRatio = True
PicWdth = .Width
PicHght = .Height
VRel = .RelativeVerticalPosition
HRel = .RelativeHorizontalPosition
VPos = .Top
HPos = .Left
Set iShp = .ConvertToInlineShape
End With
With iShp
Set Rng = .Range
.Range.Cut
End With
Call MakeImageTable(Rng, PicWdth, PicHght, BShp, VRel, HRel, VPos, HPos)
Wend
End With
End Sub
'
Sub MakeImageTable(Rng As Range, PicWdth As Single, PicHght As Single, BShp As Boolean, _
VRel As Long, HRel As Long, VPos As Single, HPos As Single)
Dim Tbl As Table, sngScl As Single
'Create & format the table
Set Tbl = Rng.Tables.Add(Range:=Rng, Numrows:=2, NumColumns:=1)
With Tbl
.Borders.Enable = True
.Columns.Width = PicWdth
.TopPadding = 0
.BottomPadding = 0
.LeftPadding = 0
.RightPadding = 0
.Spacing = 0
.Rows(1).HeightRule = wdRowHeightExactly
.Rows(1).Height = PicHght
With .Rows
.LeftIndent = 0
If BShp = True Then
.WrapAroundText = True
.HorizontalPosition = HPos
.RelativeHorizontalPosition = HRel
.VerticalPosition = VPos
.RelativeVerticalPosition = VRel
.AllowOverlap = False
End If
End With
With .Cell(1, 1).Range
With .ParagraphFormat
.SpaceBefore = 0
.SpaceAfter = 0
.LeftIndent = 0
.RightIndent = 0
.FirstLineIndent = 0
.KeepWithNext = True
End With
.Paste
End With
With .Cell(2, 1).Range
.Style = "Caption"
.End = .End - 1
.InsertAfter vbCr
.InsertCaption Label:="Figure", TitleAutoText:=" ", Title:="", _
Position:=wdCaptionPositionBelow, ExcludeLabel:=0
.Paragraphs.First.Range.Characters.Last.Text = vbNullString
.Borders(wdBorderLeft).LineStyle = wdLineStyleNone
.Borders(wdBorderRight).LineStyle = wdLineStyleNone
.Borders(wdBorderTop).LineStyle = wdLineStyleNone
End With
End With
End Sub
To work with just the selected image (or multiple images in a selected range), change:
With ActiveDocument
to:
With Selection
and change:
While .Shapes.Count > 0
With .Shapes(1)
to:
While .ShapeRange.Count > 0
With .ShapeRange(1)