var img = new Image();
img.crossOrigin = 'Anonymous';
img.onload = function () {
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
canvas.width = img.width;
canvas.height = img.height;
ctx.drawImage(img, 0, 0);
var link = document.createElement('a');
link.download = '图像名称.jpg';
link.href = canvas.toDataURL('image/jpeg', 1.0);
link.click();
canvas = null;
}
img.src = '图像链接';