The effect is in this file:
https://beautifullyfitlife.com/wp-content/themes/sight/js/script.js?ver=3.4.1
Part:
function grid_update(){
$('#loop').addClass('grid').removeClass('list');
$('#loop').find('.thumb img').attr({'width': '190', 'height': '190'});
$('#loop').find('.post')
.mouseenter(function(){
$(this)
.css('background-color','#efefef')
.find('.thumb').hide()
.css('z-index','-1');
})
.mouseleave(function(){
$(this)
.css('background-color','#f5f5f5')
.find('.thumb').show()
.css('z-index','1');
});
$('#loop').find('.post').click(function(){
location.href=$(this).find('h2 a').attr('href');
});
$.cookie('mode','grid');
Edit the mouse enter function.