function pshow(picname,xdim,ydim) {
	xdim += 16;
	ydim += 16;
	picleft=(screen.availWidth-xdim)/2;
	pictop=(screen.availHeight-ydim)/2; 
    //zoom = window.open(Bild,"z","width="+(300+plusbreite)+",height="+winheight+",left="+x+",top=0,resizable=yes,scrollbars=yes");	
	zoom=window.open(picname,"","width="+xdim+",height="+ydim+",left="+picleft+",top="+pictop+",resizable=no,scrollbars=no");	
}