让一个图片在div中居中（四种方法）

<div class="title">
<div class="flag"></div>
<div class="content">
<img src="img_p1_title.png">
</div>
</div>

.title {
width: 100%;
font-size: 0;
height: 10%;
}
.title .content img {
width: 35%;
}
/*--主要的--*/
.content{
display: inline-block;
vertical-align: middle;
}
.flag{
display: inline-block;
vertical-align: middle;
height: 100%;
width: 0;
}

<div class="title">
<img src="img_p1_title.png">
</div>

.title {
display: flex;
justify-content: center;
align-items: center;
}
.title img {
width: 35%;
}
//该方法有些旧系统不支持

<div class="title">
<span>第三种方法</span>
</div>

.title {
height: 15%;
font-size: 18px;
position: relative;
}
.title span {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}

<div class="title">
<span>第四种方法</span>
</div>

.title {
width: 200px;
height: 200px;
vertical-align: middle;
display: table-cell;
text-align: center;
}