function fixImgs(whichId, maxW) {
  var pix=document.getElementsByTagName('img');
  for (i=0; i<pix.length; i++) {
//.getElementById(whichId)
    w=pix[i].width;
    h=pix[i].height;
    if (w > maxW) {
      f=1-((w - maxW) / w);
      pix[i].width=w * f;
      pix[i].height=h * f;
      c = document.createElement('div');
      c.setAttribute('style','text-align:left;text-indent:0;');
      px_link = document.createElement('a');
      px_link.setAttribute('href', pix[i].getAttribute('src'));
      px_link.setAttribute('id','single_image');
      px_link.setAttribute('target','_blank');
      px_link_text = document.createTextNode('Полный размер');
      px_link.appendChild(px_link_text);
      c.appendChild(px_link);
      pix[i].parentNode.insertBefore(c,pix[i].nextSibling);
      $(px_link).lightBox(); 
    }
  }
}

function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

addLoadEvent(function() {
  w = document.compatMode=='CSS1Compat' && !window.opera?document.documentElement.clientWidth:document.body.clientWidth;
  w = (w-350);
  if (w < 200) w = 200;
  fixImgs('post_content', w);  // ('element ID', maximum width)
});