User:Dschwen/MegapixelDisplay.js Source: en.wikipedia.org/wiki/User:Dschwen/MegapixelDisplay.js

//
// Calculate Megapixels on image pages
//
function calculateMegapixels() {
 var data = $('.fileInfo').text();
 pixel_filter = /([\d,]+) × ([\d,]+)/;
 if(pixel_filter.test(data)) {
  pixel_filter.exec(data);
  var wt = RegExp.$1, ht = RegExp.$2
    , w = parseFloat( wt.replace(/,/,'') )
    , h = parseFloat( ht.replace(/,/,'') );
  $('.fileInfo').append( $('<span></span>').text(' (' + ((w*h)/1e6).toFixed(2) + ' Megapixel)' ) );
 }
}
if( mw.config.get('wgAction') == 'view' && mw.config.get('wgNamespaceNumber') == 6 ) $(document).ready(calculateMegapixels);