I just found out that this css works 🙂
img {
filter: grayscale(100%);
-webkit-filter: grayscale(100%);
}
img:hover {
filter: none;
-webkit-filter: grayscale(0);
}
The only thing is that it turns ALL images to B/W, as opposed to just the features images of the (custom) post types I am using. Any additional CSS?
Thanks!