if (document.images) {
	img1off = new Image();
	img1off.src = "images/illustrations/competences1.jpg";  
	img2off = new Image();
	img2off.src = "images/illustrations/competences2.jpg";  
	img3off = new Image();
	img3off.src = "images/illustrations/competences3.jpg";  
	img4off = new Image();
	img4off.src = "images/illustrations/competences4.jpg";  
	
	img1on = new Image();
	img1on.src = "images/illustrations/competences1_over.jpg";  
	img2on = new Image();
	img2on.src = "images/illustrations/competences2_over.jpg";  
	img3on = new Image();
	img3on.src = "images/illustrations/competences3_over.jpg";  
	img4on = new Image();
	img4on.src = "images/illustrations/competences4_over.jpg"; 
}