--- a/comments/forms.py	Tue Aug 04 16:58:17 2015 -0500
+++ b/comments/forms.py	Tue Sep 01 20:33:40 2015 -0500
@@ -7,6 +7,10 @@
 from django.contrib.contenttypes.models import ContentType
 
 from comments.models import Comment
+from core.html import ImageCheckError
+from core.html import image_check
+from core.markup import site_markup
+
 
 COMMENT_MAX_LENGTH = getattr(settings, 'COMMENT_MAX_LENGTH', 3000)
 
@@ -64,6 +68,18 @@
 
         return new
 
+    def clean_comment(self):
+        comment = self.cleaned_data['comment']
+        self.comment_html = None
+        if comment:
+            self.comment_html = site_markup(comment)
+            try:
+                image_check(self.comment_html)
+            except ImageCheckError as ex:
+                raise forms.ValidationError(str(ex))
+
+        return comment
+
     class Media:
         css = {
             'all': (settings.GPP_THIRD_PARTY_CSS['markitup'] +