Don't try to reload an image hover if it's not in the document.

4chan_x.user.js

@@ -2297,6 +2297,9 @@
     error: function() {
       var src, timeoutID, url,
         _this = this;
+      if (!this.parentNode) {
+        return;
+      }
       src = this.src.split('/');
       if (!(src[2] === 'images.4chan.org' && (url = Redirect.image(src[3], src[5])))) {
         if (g.DEAD) {

script.coffee

@@ -1935,6 +1935,7 @@ ImageHover =
       clientX: - 45 + parseInt style.left
       clientY:  120 + parseInt style.top
   error: ->
+    return unless @parentNode
     src = @src.split '/'
     unless src[2] is 'images.4chan.org' and url = Redirect.image src[3], src[5]
       return if g.DEAD