pixmap trouble...

Ok ok I read all the threads present in the forum about pixmap, something is clear now, but I have a problem with this

'test copy image
Graphics 640,480


Global load_image:TPixmap=LoadPixmap("gfx/world_2.png")
If load_image.format<>PF_RGBA8888 Then load_image=ConvertPixmap( load_image,PF_RGBA8888 )

Copy(load_image)


Flip
WaitKey
End


Function Copy(pix:TPixmap)
Local pix_dest:TPixmap=CreatePixmap(pix.width,pix.height,PF_RGBA8888)
Local psource:Byte Ptr
Local pdest:Byte Ptr
psize=32*4*pix.height

For k=0 To pix.width-32 Step 32
		psource=PixmapPixelPtr(pix,k,0)
		'pdest=PixmapPixelPtr(pix_Dest,pix.width-k,0)
		pdest=PixmapPixelPtr(pix_Dest,k,0)
		MemCopy(pdest,psource,psize)
	
Next

'only for test
image=ConvertToImage(pix_dest)
DrawImage image,0,0
End Function

Function ConvertToImage:timage(pix:TPixmap)
	Local size_x:Int=pix.width
	Local size_y:Int=Pix.height
	Local pdest:Byte Ptr
	Local psource:Byte Ptr
	psource=PixmapPixelPtr(pix,0,0)
	Local psize:Int=size_x*size_y*4 '4 bytes per pixel assuming RGBA8888 format pixmap
	temp_image:TImage=CreateImage(size_x,size_y,1,iflags|DYNAMICIMAGE) 'create dummy image in case we want to do realtime conversion between pixmaps and images/textures
	temp_pixmap:TPixmap=LockImage(temp_image,0,False,True) 'Lock our dummy image so we can draw to it
	pdest=PixmapPixelPtr(temp_pixmap,0,0) 'Set our destination pointer to the image's pixmap
	MemCopy(pdest,psource,psize) 'Copy the pixels from the pixmap in memory to the image/texture's pixmap
	UnlockImage(temp_image) 'Let the image be rendered now
	Return temp_image
End Function

The goal is copy from a pixmap to another one...
Why I get only a black image?