Hocam zaten dışında div varmış. Şu şekilde düzenledim kendime göre ama garip birşey oldu :)

@keyframes zoomYapBaba {
from {width:180px; height:180px;}
to {width:190px; height:190px;}
}

@keyframes zoomOutBaba {
from {width:190px; height:190px;}
to {width:180px; height:180px;}
}


.attachment-featured.size-featured.wp-post-image{
width:180px;
height:180px;
animation:zoomOutBaba;
animation-duration: 0.4s;
}


.attachment-featured.size-featured.wp-post-image:hover{
animation:zoomYapBaba;
animation-timing-function: ease-out;
animation-duration: 0.4s;
width:180px;
height:180px;
}


#page .featured-thumbnail {
width:180px;
height:180px;
overflow:hidden;
}