The following macro will insert a linked thumbnail image at the cursor, subject to the provisos mentioned by Andrew. Call it from a macro that provides the image path and optionally the screen tip text.
Code:
Sub InsThumbNail(strPath As String, _
Optional strTipText As String = "Link to full size image")
'Graham Mayor - http://www.gmayor.com - Last updated - 20 May 2018
Dim oShape As InlineShape
Set oShape = Selection.InlineShapes.AddPicture(FileName:=strPath, _
LinkToFile:=False, _
SaveWithDocument:=True)
With oShape
.LockAspectRatio = msoTrue
.Width = InchesToPoints(1)
ActiveDocument.Hyperlinks.Add Anchor:=.Range, _
Address:=strPath, _
SubAddress:="", _
ScreenTip:=strTipText, _
TextToDisplay:=.Range.Text
End With
lbl_Exit:
Set oShape = Nothing
Exit Sub
End Sub