Pour que l'image s'allume au survol de la souris il faut mettre ça:

/* image opaque */ img { -moz-transition: opacity 0.4s linear 0s; -webkit-transition: opacity 0.4s linear 0s; transition: opacity 0.4s linear 0s; opacity: 0.5; } /* image claire */ img:hover { -moz-transition: opacity 0.4s linear 0s; -webkit-transition: opacity 0.4s linear 0s; transition: opacity 0.4s linear 0s; opacity: 1; }