CODE -->

Option Explicit
Dim drgImage As Picture
Dim srcRow As Long
Dim srcCol As Long

Private Sub Form_Load()
    ' Set up a trivial msflexgrid with an image from an imagelist
    MSFlexGrid1.Rows = 4
    MSFlexGrid1.Cols = 4
    MSFlexGrid1.Row = 3
    MSFlexGrid1.Col = 3
    Set MSFlexGrid1.CellPicture = ImageList1.ListImages(1).Picture
End Sub

'MSFlexgrid DragMode property should be 0 - vbDragManual. Generally this is the default.
Private Sub MSFlexGrid1_MouseDown(Button As Integer, Shift As Integer, x As Single, y As Single)
    If Button = vbLeftButton Then
        With Me.MSFlexGrid1
            If .CellPicture <> 0 Then
                .DragIcon = .CellPicture
                ' capture source cell info
                Set drgImage = .CellPicture
                srcRow = .Row
                srcCol = .Col
                .Drag vbBeginDrag 'start a drag operation.
            End If
        End With
    End If
End Sub

Private Sub MSFlexGrid1_DragOver(Source As Control, x As Single, y As Single, State As Integer)
    ' Allow default control behaviour to highlight potential target cell
    If Source Is Me.MSFlexGrid1 Then
        MSFlexGrid1.Col = MSFlexGrid1.MouseCol
        MSFlexGrid1.Row = MSFlexGrid1.MouseRow
    End If
End Sub

Private Sub MSFlexGrid1_DragDrop(Source As Control, x As Single, y As Single)
    If Source Is Me.MSFlexGrid1 Then
        With Me.MSFlexGrid1
            Set .CellPicture = drgImage ' copy source image into target
            
            .Row = srcRow
            .Col = srcCol
             Set .CellPicture = Nothing ' this is a cut and paste, so delete image in source cell
             ' Rehighlight cell we dropped on as that is generally expected behaviour
             .Row = .MouseRow
             .Col = .MouseCol
        End With
    End If
End Sub