diff --git a/src/calibre/customize/conversion.py b/src/calibre/customize/conversion.py
index 4f2b279f85..273bb9ebf7 100644
--- a/src/calibre/customize/conversion.py
+++ b/src/calibre/customize/conversion.py
@@ -109,6 +109,10 @@ class InputFormatPlugin(Plugin):
     #: convenience method, :method:`get_image_collection`.
     is_image_collection = False
 
+    #: If set to True, the input plugin will perform special processing
+    #: to make its output suitable for viewing
+    for_viewer = False
+
     #: Options shared by all Input format plugins. Do not override
     #: in sub-classes. Use :member:`options` instead. Every option must be an
     #: instance of :class:`OptionRecommendation`.
diff --git a/src/calibre/ebooks/epub/input.py b/src/calibre/ebooks/epub/input.py
index 3f8b563d96..fd1e4733e1 100644
--- a/src/calibre/ebooks/epub/input.py
+++ b/src/calibre/ebooks/epub/input.py
@@ -53,7 +53,6 @@ class EPUBInput(InputFormatPlugin):
             traceback.print_exc()
         return False
 
-    @classmethod
     def rationalize_cover(self, opf, log):
         guide_cover, guide_elem = None, None
         for guide_elem in opf.iterguide():
@@ -78,7 +77,8 @@ class EPUBInput(InputFormatPlugin):
 
         # Remove from spine as covers must be treated
         # specially
-        spine[0].getparent().remove(spine[0])
+        if not self.for_viewer:
+            spine[0].getparent().remove(spine[0])
         guide_elem.set('href', 'calibre_raster_cover.jpg')
         from calibre.ebooks.oeb.base import OPF
         t = etree.SubElement(elem[0].getparent(), OPF('item'),
diff --git a/src/calibre/ebooks/oeb/iterator.py b/src/calibre/ebooks/oeb/iterator.py
index 4910bf4e10..9b9158b37e 100644
--- a/src/calibre/ebooks/oeb/iterator.py
+++ b/src/calibre/ebooks/oeb/iterator.py
@@ -134,6 +134,7 @@ class EbookIterator(object):
         if hasattr(plumber.opts, 'no_process'):
             plumber.opts.no_process = True
 
+        plumber.input_plugin.for_viewer = True
         self.pathtoopf = plumber.input_plugin(open(plumber.input, 'rb'),
                 plumber.opts, plumber.input_fmt, self.log,
                 {}, self.base)