img-rounded 添加 border-radius:6px 來獲得圖片圓角
img-circle 添加 border-radius:50% 來讓整個圖片變成圓形
img-thumbnail 添加一些內邊距（padding）和一個灰色的邊框
img-responsive 圖片響應式
1、img-rounded
<!doctype html>
<html lang="en">
<head>
<!--網(wǎng)站編碼格式，UTF-8 國際編碼，GBK或 gb2312 中文編碼-->
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="Keywords" content="關鍵詞一，關鍵詞二">
<meta name="Description" content="網(wǎng)站描述內容">
<meta name="Author" content="Yvette Lau">
<meta name = "viewport" content = " width = device-width, initial-scale = 1 ">
<title>BootstrapDemo</title>
<!--css js 文件的引入-->
<link rel="stylesheet" type="text/css" href="../bootstrap-3.3.5-dist/css/bootstrap.min.css">
</head>
<body style="padding: 20px;">
<div class = "container">
<img src = "5.jpg" class="img-rounded" >
</div>
</body>
</html>
.img-rounded{border-radius:6px;}
2、img-circle
<body style="padding: 20px;">
<div class = "container">
<img src = "5.jpg" class="img-circle" >
</div>
</body>
.img-circle{border-radius:50%;}
效果(因為本圖片的寬高大小不同，所以呈現(xiàn)出橢圓，如果將width和height設置相同，那么會呈現(xiàn)出一個圓)：
3、img-thumbnail
<body style="padding: 20px;">
<div class = "container">
<img src = "5.jpg" class="img-thumbnail" >
<img src = "4.jpg" class="img-thumbnail" >
<img src = "3.jpg" class="img-thumbnail" >
</div>
</body>
.img-thumbnail{display:inline-block;max-width:100%;height:auto;padding:4px;line-height:1.42857143;
background-color:#FFF;border:1px solid #DDD;border-radius:4px;transition:all 0.2s ease-in-out;}
4、img-responsize
<body style="padding: 20px;">
<div class = "container" style = "width:150px;">
<img src = "5.jpg" class="img-responsive" width="400px" >
</div>
</body>
.img-responsive{display:block;max-width:100%;height:auto;}
