.diplomes1 a{float:left;width:140px;height:140px;background:url(img/impressions/diplomes/1.png)}
.diplomes1 a:hover{background:url(img/impressions/diplomes/1_thumbs.png)}
.diplomes2 a{float:left;width:140px;height:140px;background:url(img/impressions/diplomes/2.png)}
.diplomes2 a:hover{background:url(img/impressions/diplomes/2_thumbs.png)}
.diplomes3 a{float:left;width:140px;height:140px;background:url(img/impressions/diplomes/3.png)}
.diplomes3 a:hover{background:url(img/impressions/diplomes/3_thumbs.png)}