Use childNodes[2] for finding file resolution

ExLinks support vanilla 4chan and can add in its reverse image search link to the .fileText before 4chan X manages to parse it. As a result, 4chan X ends up looking at the reverse image search link for dimensions instead of the correct text element. Using childNodes[2] instead of lastChild fixes this.

src/General/Post.coffee

@@ -148,7 +148,7 @@ class Post
     @file.isImage = /(jpg|png|gif)$/i.test @file.name
     @file.isVideo = /webm$/i.test @file.name
     if @file.isImage or @file.isVideo
-      @file.dimensions = fileText.lastChild.data.match(/\d+x\d+/)[0]
+      @file.dimensions = fileText.childNodes[2].data.match(/\d+x\d+/)[0]
 
   cleanup: (root, post) ->
     for node in $$ '.mobile', root