src需要注意，不同源情况下图片有跨域情况，需要后台开放权限，如果是前端本地图片可以动态获取地址
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
<a onclick="downCom()">下载图片</a>
<img ref="imgaa" id="imgaa" src="https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fwww.duanlonglong.com%2Fuploads%2Fallimg%2F210609%2F1-2106091644394P.png&refer=http%3A%2F%2Fwww.duanlonglong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1645319184&t=6ec886be2d65e16599e03e88f36af984" >
<!-- 如果是vue动态绑定img的src属性 绝对路径下 fatherList.imgSrc代表../../../image/tupian.png-->
<!-- <img :src="require('' + fatherList.imgSrc)" alt="" ref="image" /> -->
</body>
<script type="text/javascript">
function downCom() {
// src需要注意，不同源情况下图片有跨域情况，需要后台开放权限，如果是前端本地图片可以动态获取地址 如：
// vue下 let data = this.$refs.imgaa; let src = data.src;
// vue与js下 document.querySelector("#imgaa").src;
let src = 'https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fwww.duanlonglong.com%2Fuploads%2Fallimg%2F210609%2F1-2106091644394P.png&refer=http%3A%2F%2Fwww.duanlonglong.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1645319184&t=6ec886be2d65e16599e03e88f36af984';
let name = '段龙龙博客图片1';
// src为图片地址,name为下载后图片的命名
this.downloadByBlob(src, name);
debugger
}
function downloadByBlob(url, name) {
let image = new Image()
image.setAttribute('crossOrigin', 'anonymous')
image.src = url
image.onload = () => {
let canvas = document.createElement('canvas')
canvas.width = image.width
canvas.height = image.height
let ctx = canvas.getContext('2d')
ctx.drawImage(image, 0, 0, image.width, image.height)
canvas.toBlob((blob) => {
let url = URL.createObjectURL(blob)
download(url, name)
// 用完释放URL对象
URL.revokeObjectURL(url)
})
}
}
function download(href, name) {
let eleLink = document.createElement('a')
eleLink.download = name
eleLink.href = href
eleLink.click()
eleLink.remove()
}
</script>
</html>