javascript:

function Instagram(key)
{
	var metas = document.getElementsByTagName('meta');

	for (var i = 0; i < metas.length; i++)
  {
		if (metas[i].getAttribute("property") == key)
    {
			return metas[i].getAttribute("content");
		}
	}

	return '';
}

var j = Instagram('og:image');
var k = ['\/s320x320', '\/p320x320', '\/s480x480', '\/p480x480', '\/s640x640', '\/p640x640', '\/s750x750', '\/p750x750'];

if (j)
{
  for (var i = 0; i < k.length; i++)
  {
    if (j.indexOf(k[i]) != -1)
    {
      j = j.replace(k[i], '');
    }
  }
location.href = j;
}