szurubooru/public_html/media/css/post-list.css

.posts img {
	border: 1px solid #ddd;
	box-shadow: 0.25em 0.25em #eee;
	margin: 0.5em;
	padding: 0;
	width: 140px;
	height: 140px;
}

.posts .post-type-flash img {
	border-color: #dd5;
	box-shadow: 0.25em 0.25em #eeb, 0.1em 0.1em 0.5em 0.1em rgba(238,238,187,0.5);
}

.posts a:focus img,
.posts a:hover img {
	border: 1px solid firebrick;
	box-shadow: 0.25em 0.25em pink;
	opacity: .9;
}