nginx配置：

location ~ /(mmbiz|sz_mmbiz)(.*)/ {
    proxy_pass         https://mmbiz.qpic.cn;
    proxy_set_header   Host             "mmbiz.qpic.cn"; #微信平台域名
    proxy_set_header   Referer          "";
    proxy_buffer_size 128k; #缓存区设置，不加的话，图片过大可能造成第一次加载失败
    proxy_buffers   32 128k;
    proxy_busy_buffers_size 128k;
    expires 365d;
    valid_referers none blocked *.xxxx.xxxx.com; #只允许xxx域名
    if ($invalid_referer) {
        return 404;
       }
 }

sub_filter "http://mmbiz.qpic.cn" "";
sub_filter_once off;