diff --git a/resources/viewer/images.js b/resources/viewer/images.js
index cc6e6d47e5..ea68009254 100644
--- a/resources/viewer/images.js
+++ b/resources/viewer/images.js
@@ -7,6 +7,7 @@
 function scale_images() {
     $("img:visible").each(function() {
         var offset = $(this).offset();
+        //window.py_bridge.debug(window.getComputedStyle(this, '').getPropertyValue('max-width'));
         $(this).css("max-width", (window.innerWidth-offset.left-5)+"px");
         $(this).css("max-height", (window.innerHeight-5)+"px");
     });
diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index b8557aea98..4f894ce088 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -563,6 +563,16 @@ class MobiReader(object):
                     recindex = attrib.pop(attr, None) or recindex
                 if recindex is not None:
                     attrib['src'] = 'images/%s.jpg' % recindex
+                for attr in ('width', 'height'):
+                    if attr in attrib:
+                        val = attrib[attr]
+                        if val.lower().endswith('em'):
+                            try:
+                                nval = float(val[:-2])
+                                nval *= 16 * (168.451/72) # Assume this was set using the Kindle profile
+                                attrib[attr] = "%dpx"%int(nval)
+                            except:
+                                del attrib[attr]
             elif tag.tag == 'pre':
                 if not tag.text:
                     tag.tag = 'div'
diff --git a/src/calibre/ebooks/oeb/stylizer.py b/src/calibre/ebooks/oeb/stylizer.py
index 9f50796615..d0e394b9e5 100644
--- a/src/calibre/ebooks/oeb/stylizer.py
+++ b/src/calibre/ebooks/oeb/stylizer.py
@@ -411,6 +411,7 @@ class Style(object):
         return result
 
     def _unit_convert(self, value, base=None, font=None):
+        ' Return value in pts'
         if isinstance(value, (int, long, float)):
             return value
         try:
@@ -447,6 +448,9 @@ class Style(object):
                 result = value * 0.40
         return result
 
+    def pt_to_px(self, value):
+        return (self._profile.dpi / 72.0) * value
+
     @property
     def fontSize(self):
         def normalize_fontsize(value, base):