图像叠加时不需要的填充底部？

Question

我在图像类中添加了一个填充底部，并希望在图像上悬停覆盖，但它会延伸到图像之外，包括添加的填充。有没有办法确保悬停跨越图像的宽度和高度没有填充？谢谢！

.work-image {
  width: 100%;
  height: 100%;
  position: relative;
  padding-bottom: 15px;
  vertical-align: bottom;
}
.work-image img {
  width: 100%;
}

.work-image:after, .work-image:before {
  opacity: 0;
  position: absolute;
  transition: all 0.5s;
  -webkit-transition: all 0.5s;
}
.work-image:after {
  top: 0;
  left: 0;
  width: 100%;
  height:100%;
  content: '\A';
  background:rgba(0,0,0,0.6);
}
.work-image:before {
  top: 50%;
  z-index: 1;
  width: 100%;
  color: #fff;
  text-align: center;
  transform: translateY(-50%);
  content: attr(data-content);
}

.work-image:hover:after, .work-image:hover:before {
  opacity:1;
}

<div data-content="Here is a caption" class="work-image">
  <img src="http://i65.tinypic.com/2l8w0hc.jpg" alt="" />
</div>

<div data-content="Here is a caption" class="work-image">
  <img src="http://i64.tinypic.com/2zodetx.jpg" alt="" />
</div>

Answer 1

将vertical-align: bottom;从.work-image移至.work-image img，并将padding-bottom替换为margin-bottom。

.work-image {
  width: 100%;
  height: 100%;
  position: relative;
  margin-bottom: 15px;      
}
.work-image img {
  width: 100%;
  vertical-align: bottom;
}

.work-image:after, .work-image:before {
  opacity: 0;
  position: absolute;
  transition: all 0.5s;
  -webkit-transition: all 0.5s;
}
.work-image:after {
  top: 0;
  left: 0;
  width: 100%;
  height:100%;
  content: '\A';
  background:rgba(0,0,0,0.6);
}
.work-image:before {
  top: 50%;
  z-index: 1;
  width: 100%;
  color: #fff;
  text-align: center;
  transform: translateY(-50%);
  content: attr(data-content);
}

.work-image:hover:after, .work-image:hover:before {
  opacity:1;
}

<div data-content="Here is a caption" class="work-image">
  <img src="http://i65.tinypic.com/2l8w0hc.jpg" alt="" />
</div>

<div data-content="Here is a caption" class="work-image">
  <img src="http://i64.tinypic.com/2zodetx.jpg" alt="" />
</div>