function pop_img(img)
{
img1= new Image();
img1.src=(img);
imgControll(img);
}
function imgControll(img)
{
if((img1.width!=0)&&(img1.height!=0))
{
popup_img(img);
}
else
{
controller="imgControll('"+img+"')";
intervalID=setTimeout(controller,20);
}
}
function popup_img(img)
{
W=img1.width;
H=img1.height;
LeftPosition = (screen.width) ? (screen.width-W)/2 : 0;
TopPosition = (screen.height) ? (screen.height-H)/2 : 0;
option="width="+W+",height="+H+",top="+TopPosition+",left="+LeftPosition+"";
imgWin=window.open("","",option);
imgWin.document.write("PREVIEW IMAGE");
imgWin.document.write("");
imgWin.document.write("![](\""+img+"\")
");
imgWin.document.write("");
imgWin.document.close();
}