diff --git a/src/calibre/ebooks/conversion/utils.py b/src/calibre/ebooks/conversion/utils.py
index 8a339afe4c..16ef4c86e2 100644
--- a/src/calibre/ebooks/conversion/utils.py
+++ b/src/calibre/ebooks/conversion/utils.py
@@ -490,11 +490,12 @@ class HeuristicProcessor(object):
         applied to wrapping divs.  This is because many ebook devices don't support margin:auto
         All other html is converted to text.
         '''
-        hr_open = '<div id="scenebreak" style="margin-left: 45%; margin-right: 45%; margin-top:1.5em; margin-bottom:1.5em">'
+        hr_open = '<div id="scenebreak" style="margin-left: 45%; margin-right: 45%; margin-top:1.5em; margin-bottom:1.5em; page-break-before:avoid">'
         if re.findall('(<|>)', replacement_break):
             if re.match('^<hr', replacement_break):
                 if replacement_break.find('width') != -1:
                    width = int(re.sub('.*?width(:|=)(?P<wnum>\d+).*', '\g<wnum>', replacement_break))
+                   replacement_break = re.sub('(?i)(width=\d+\%?|width:\s*\d+(\%|px|pt|em)?;?)', '', replacement_break)
                    divpercent = (100 - width) / 2
                    hr_open = re.sub('45', str(divpercent), hr_open)
                    scene_break = hr_open+replacement_break+'</div>'
@@ -642,7 +643,7 @@ class HeuristicProcessor(object):
             # or 'hard' scene breaks are replaced, depending on which is in use
             # Otherwise separator lines are centered, use a bit larger margin in this case
             replacement_break = getattr(self.extra_opts, 'replace_scene_breaks', None)
-            if replacement_break is not None:
+            if replacement_break != '':
                 replacement_break = self.markup_user_break(replacement_break)
                 if len(scene_break.findall(html)) >= 1:
                     html = scene_break.sub(replacement_break, html)
diff --git a/src/calibre/gui2/convert/heuristics.py b/src/calibre/gui2/convert/heuristics.py
index 77fadf059c..5e7e4aa506 100644
--- a/src/calibre/gui2/convert/heuristics.py
+++ b/src/calibre/gui2/convert/heuristics.py
@@ -27,8 +27,8 @@ class HeuristicsWidget(Widget, Ui_Form):
                  'dehyphenate', 'renumber_headings']
                 )
         self.db, self.book_id = db, book_id
-        self.rssb_defaults = [u'', u'<hr />', u'* * *', u'• • •', u'✦ ✦ ✦',
-                u'✮ ✮ ✮', u'☆ ☆ ☆', u'❂ ❂ ❂', u'✣ ✣ ✣', u'❖ ❖ ❖', u'☼ ☼ ☼', u'✠ ✠ ✠']
+        self.rssb_defaults = [u'', u'<hr />', u'∗ ∗ ∗', u'• • •', u'♦ ♦ ♦',
+                u'† †', u'‡ ‡ ‡', u'∞ ∞ ∞', u'¤ ¤ ¤', u'§']
         self.initialize_options(get_option, get_help, db, book_id)
 
         self.load_histories()
diff --git a/src/calibre/manual/conversion.rst b/src/calibre/manual/conversion.rst
index ecd8609ecc..60f8a10fc6 100644
--- a/src/calibre/manual/conversion.rst
+++ b/src/calibre/manual/conversion.rst
@@ -316,9 +316,19 @@ remove all non-breaking-space entities, or may include false positive matches re
 
 :guilabel:`Replace scene breaks`
     If this option is configured then |app| will replace scene break markers it finds with the replacement text specified by the
-    user. In general you should avoid using html tags, |app| will discard any tags and use pre-defined markup.  <hr />
-    tags, i.e. horizontal rules, are an exception.  These can optionally be specified with styles, if you choose to add your own
-    style be sure to include the 'width' setting, otherwise the style information will be discarded.
+    user.  Please note that some ornamental characters may not be supported across all reading devices.
+    
+    In general you should avoid using html tags, |app| will discard any tags and use pre-defined markup.  <hr />
+    tags, i.e. horizontal rules, and <img> tags are exceptions.  Horizontal rules can optionally be specified with styles, if you 
+    choose to add your own style be sure to include the 'width' setting, otherwise the style information will be discarded.  Image 
+    tags can used, but |app| does not provide the ability to add the image during conversion, this must be done after the fact using 
+    the 'Tweak Epub' feature, or Sigil.
+        
+        Example image tag (place the image within an 'Images' folder inside the epub after conversion):
+            <img style="width:10%" src="../Images/scenebreak.png" />
+        
+        Example horizontal rule with styles:
+            <hr style="width:20%;padding-top: 1px;border-top: 2px ridge black;border-bottom: 2px groove black;"/>
  
 :guilabel:`Remove unnecessary hyphens`
     |app| will analyze all hyphenated content in the document when this option is enabled.  The document itself is used