CSS border-mage-source属性用于设置图像路径。您可以尝试运行以下代码来实现border-image-source属性：
<html>
<head>
<style>
#borderimg1 {
border: 15px solid transparent;
padding: 15px;
border-image-source: url(https://nhooo.com/css/images/border.png);
border-image-repeat: round;
border-image-slice: 50;
}
</style>
</head>
<body>
<p id = "borderimg1">This is image border example.</p>
</body>
</html>