jQuery.fn.preloadimgs = function() {
	return this.each(function() {
	    jQuery(this).find('img[longdesc*=jpg]').each(function() { 
			jQuery(this).attr('src',jQuery(this).attr('longdesc')).attr('longdesc','');
		});
	});
		
}

jQuery.fn.preloadvisible = function() {
	return this.each(function() {
	    jQuery(this).find('img[longdesc*=jpg]:visible').each(function() { 
			jQuery(this).attr('src',jQuery(this).attr('longdesc')).attr('longdesc','');
		});
	});
		
}