Sub ReplaceImages()
Dim str As String
Dim captionTag As String
Dim imageTag As String
'Dim objShape As Variant Type Mismatch?
Dim fileName As String
Application.ScreenUpdating = False
Application.DisplayAlerts = False
Application.EnableEvents = False
'Select directory to match .PNG to figure in document
Set SelectFolder = Application.FileDialog(msoFileDialogFolderPicker)
    With SelectFolder
        .Title = "Select Directory"
        .AllowMultiSelect = False
        If .Show <> -1 Then GoTo ResetSettings
        sPath = .SelectedItems(1) & "\"
    End With
sFile = Dir(sPath & "*png")
Do While sFile <> ""
    fileName = sFile
    MsgBox fileName
    imageTag = BetweenParentheses(fileName)
    For Each objShape In ActiveDocument.Shapes
    If objShape.Type = msoTextBox Then
        Set shapePicture = objShape
       str = objShape.TextFrame.TextRange.Text
        If InStr(str, "(") > 0 Then
            captionTag = BetweenParentheses(objShape.TextFrame.TextRange)
            If captionTag = imageTag Then
                If InStr(str, "Figure") > 0 Then
                    Dim firstTerm As String
                    Dim secondTerm As String
                    Dim caption As String
                    firstTerm = "F"
                    secondTerm = ")"
                    Dim startPos As Long
                    Dim stopPos As Long
                    Dim nextPosition As Long
                    nextPosition = 1
                    caption = objShape.TextFrame.TextRange.Text
                    Do Until nextPosition = 0
                   startPos = InStr(nextPosition, caption, firstTerm, vbTextCompare) - 1
                        stopPos = InStr(startPos, caption, secondTerm, vbTextCompare) + 1
                        caption = Mid$(caption, startPos + Len(firstTerm), stopPos - startPos - Len(firstTerm))
                        nextPosition = InStr(stopPos, caption, firstTerm, vbTextCompare)
                    caption.Copy 'This is where the error is
                End If
            End If
        End If
    End If
Next objShape
sFile = Dir
ResetSettings:
Application.ScreenUpdating = False
Application.DisplayAlerts = False
Application.EnableEvents = False