Probably you need to show your code. Will the code below work for you (replace c:\image010.gif with your file)?

local oForm
oForm = Createobject('myForm')
oForm.show
READ event

return
*----------------
Define Class myForm As Form

  Procedure Init
 	this.AddObject("image1","Image")
 	WITH this.image1
 		.visible=.t.
 		.picture="c:\image010.gif"
 		.left=1
 		.top=1
 	ENDWITH
	ON KEY LABEL ALT+t oForm.image1.visible=.t.
	ON KEY LABEL ALT+f oForm.image1.visible=.f.
  Endproc
  Procedure Destroy
	ON KEY LABEL ALT+t
	ON KEY LABEL ALT+f
	CLEAR EVENTS
  Endproc
  
Enddefine

>Sorry !!!
>If I used This code:
>ThisForm.Image1.Picture = "C:\Proyect\Pictures\Cust.Gif"
>To Display a GIF Picture.
>And When I Handle of Change The Property Visible of is Image o Picture, ThisForm.Image1.Visible = .T. Or ThisForm.Image1.Visible = .F., Not Operate.
>Do You understand me ??