diff --git a/src/calibre/ebooks/mobi/writer.py b/src/calibre/ebooks/mobi/writer.py
index a320bd7691..ec8b393c22 100644
--- a/src/calibre/ebooks/mobi/writer.py
+++ b/src/calibre/ebooks/mobi/writer.py
@@ -186,10 +186,12 @@ class Serializer(object):
                 if attr == 'href':
                     if self.serialize_href(val, item):
                         continue
-                elif attr == 'src' and val in hrefs:
-                    index = self.images[val]
-                    buffer.write('recindex="%05d"' % index)
-                    continue
+                elif attr == 'src':
+                    href = item.abshref(val)
+                    if href in hrefs:
+                        index = self.images[href]
+                        buffer.write('recindex="%05d"' % index)
+                        continue
                 buffer.write(attr)
                 buffer.write('="')
                 self.serialize_text(val, quot=True)
diff --git a/src/calibre/ebooks/oeb/base.py b/src/calibre/ebooks/oeb/base.py
index f5262c977f..f90b5defea 100644
--- a/src/calibre/ebooks/oeb/base.py
+++ b/src/calibre/ebooks/oeb/base.py
@@ -914,11 +914,11 @@ class OEBBook(object):
             cover = self.manifest.hrefs[href]
         elif xpath(html, '//h:img[position()=1]'):
             img = xpath(html, '//h:img[position()=1]')[0]
-            href = img.get('src')
+            href = spine0.abshref(img.get('src'))
             cover = self.manifest.hrefs[href]
         elif xpath(html, '//h:object[position()=1]'):
             object = xpath(html, '//h:object[position()=1]')[0]
-            href = object.get('data')
+            href = spine0.abshref(object.get('data'))
             cover = self.manifest.hrefs[href]
         elif xpath(html, '//svg:svg[position()=1]'):
             svg = copy.deepcopy(xpath(html, '//svg:svg[position()=1]')[0])
diff --git a/src/calibre/ebooks/oeb/transforms/flatcss.py b/src/calibre/ebooks/oeb/transforms/flatcss.py
index 98f918aebf..2e6e64cdfa 100644
--- a/src/calibre/ebooks/oeb/transforms/flatcss.py
+++ b/src/calibre/ebooks/oeb/transforms/flatcss.py
@@ -218,7 +218,9 @@ class CSSFlattener(object):
         for child in node:
             self.flatten_node(child, stylizer, names, styles, psize, left)
 
-    def flatten_head(self, head, stylizer, href):
+    def flatten_head(self, item, stylizer, href):
+        html = item.data
+        head = html.find(XHTML('head'))
         for node in head:
             if node.tag == XHTML('link') \
                and node.get('rel', 'stylesheet') == 'stylesheet' \
@@ -227,6 +229,7 @@ class CSSFlattener(object):
             elif node.tag == XHTML('style') \
                  and node.get('type', CSS_MIME) in OEB_STYLES:
                 head.remove(node)
+        href = item.relhref(href)
         etree.SubElement(head, XHTML('link'),
             rel='stylesheet', type=CSS_MIME, href=href)
         if stylizer.page_rule:
@@ -259,7 +262,5 @@ class CSSFlattener(object):
         css = ''.join(".%s {\n%s;\n}\n\n" % (key, val) for key, val in items)
         href = self.replace_css(css)
         for item in self.oeb.spine:
-            html = item.data
             stylizer = self.stylizers[item]
-            head = html.find(XHTML('head'))
-            self.flatten_head(head, stylizer, href)
+            self.flatten_head(item, stylizer, href)