.gl {
width: 300px;
height: 300px;
display: inline-block;
max-width: 300px;
max-height: 200px;
background-color: #fff;
position: relative;
background-image: url('https://i.ibb.co/QfLmLrT/image.jpg');
background-repeat: no-repeat;
background-size: contain;
}
.gl:before {
content: '';
position: absolute;
background-color: rgba(0, 0, 0, .5);
left: 0;
top: 0;
width: 100%;
height: 100%;
}
a {
color: red;
font-size: 30px;
cursor: pointer;
}
<div class="gl">
<button>Know More</button>
</div>
您只需将按钮移动到顶层,在具有背景图像和蒙版的层之上: