Try this basic sample and let me know if works for you:
Code:
Option Explicit

Dim intY As Integer
Dim intX As Integer

Private Sub Picture1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
    intX = X
    intY = Y
    Picture1.Drag vbBeginDrag
End Sub

Private Sub Form_DragDrop(Source As Control, X As Single, Y As Single)
    Source.Move X - intX, Y - intY
    Source.Drag vbEndDrag
End Sub