fix(image): remove unnecessary hostname check

- checked by url_for()
  * https://github.com/hexojs/hexo-util/blob/b34456a7a56ae905c13a3541272176ef520a0488/lib/url_for.js#L31

lib/renderer.js

@@ -3,7 +3,6 @@
 const marked = require('marked');
 const { encodeURL, slugize, stripHTML, url_for, isExternalLink } = require('hexo-util');
 const MarkedRenderer = marked.Renderer;
-const { parse } = require('url');
 const { sep } = require('path');
 let hexo;
 
@@ -93,16 +92,15 @@ class Renderer extends MarkedRenderer {
     const { relative_link } = hexo.config;
     const { options } = this;
     const { lazyload, prependRoot, postId } = options;
-    const { hostname } = parse(href);
 
-    if (!hostname && !relative_link && prependRoot) {
+    if (!relative_link && prependRoot) {
       if (postId) {
         const PostAsset = hexo.model('PostAsset');
         // slug requires platform-specific path
         const asset = PostAsset.findOne({ post: postId, slug: href.replace(/\/|\\/g, sep) });
         if (asset) href = encodeURL(('/' + asset.path).replace(/\\/g, '/').replace(/\/{2,}/g, '/'));
       }
-      href = url_for.call(options, href);
+      href = url_for.call(hexo, href);
     }
 
     let out = `<img src="${encodeURL(href)}"`;