img.bg{
position: absolute;
left: 0;
top: 0;
z-index: 1;
width: 100%;
height: auto;
opacity: 0.5;
}
.текстовыйблок{
position: relative;
z-index: 2;
}
<a href="<?php echo get_permalink(); ?>">ХХХХХХХХ</a>
.block{
opacity: 0;
pointer-events: none;
}
.block.visible{
opacity: 1;
pointer-events: all;
}