Modify code to make floating Pictue stay within form boundries

How can i modify this code so picture does not disappear off the form
Sub MovePic()
Dim x As Single, y As Single, velocity As Single, angle As Single, vangle As Single
CenterPic

Me.picJackpot.ZOrder 0
    velocity = 2
    angle = Rnd * 6.283
    x = picJackpot.Left: y = picJackpot.Top
   
    Do
        If Rnd < 0.1 Then vangle = (Rnd - 0.5) * 0.5 'Change direction velocity randomly 10%chance
        angle = angle + (vangle + 6.283) Mod 6.283 'change direction
        x = x + Cos(angle) * velocity 'move position
        y = y + Sin(angle) * velocity
        picJackpot.Move x, y 'move image
        DoEvents 'threading
    Loop While mStopJackPot = False 'Forms.Count Or yourchoise
End Sub