diff --git a/README.txt b/README.txt
index a269591..3420b81 100755
--- a/README.txt
+++ b/README.txt
@@ -19,13 +19,12 @@ Let's start with creating a few example concepts, putting them in a
 top-level loops container and a concept manager:
 
   >>> from loops import Loops
-  >>> loops = Loops()
   >>> site['loops'] = Loops()
-  >>> loops = site['loops']
+  >>> loopsRoot = site['loops']
 
   >>> from loops.concept import ConceptManager, Concept
-  >>> loops['concepts'] = ConceptManager()
-  >>> concepts = loops['concepts']
+  >>> loopsRoot['concepts'] = ConceptManager()
+  >>> concepts = loopsRoot['concepts']
   >>> cc1 = Concept()
   >>> concepts['cc1'] = cc1
   >>> cc1.title
@@ -78,8 +77,8 @@ Resources and what they have to do with Concepts
 We first need a resource manager:
     
   >>> from loops.resource import ResourceManager, Document
-  >>> loops['resources'] = ResourceManager()
-  >>> resources = loops['resources']
+  >>> loopsRoot['resources'] = ResourceManager()
+  >>> resources = loopsRoot['resources']
 
 A common type of resource is a document:
       
@@ -90,10 +89,35 @@ A common type of resource is a document:
   >>> doc1.data
   u''
   >>> doc1.contentType
-  u'text/xml'
+  ''
 
 Another one is a media asset:
 
+  >>> from loops.resource import MediaAsset
+  >>> img = MediaAsset(u'A png Image')
+
+For testing we use some simple files from the tests directory:
+      
+  >>> from loops import tests
+  >>> import os
+  >>> path = os.path.join(*tests.__path__)
+  >>> img.data = open(os.path.join(path, 'test_icon.png')).read()
+  >>> img.getSize()
+  381
+  >>> img.getImageSize()
+  (16, 16)
+  >>> img.contentType
+  'image/png'
+
+  >>> pdf = MediaAsset(u'A pdf File')
+  >>> pdf.data = open(os.path.join(path, 'test.pdf')).read()
+  >>> pdf.getSize()
+  25862
+  >>> pdf.getImageSize()
+  (-1, -1)
+  >>> pdf.contentType
+  'application/pdf'
+
 We can associate a resource with a concept by assigning it to the concept:
 
   >>> cc1.assignResource(doc1)
@@ -129,8 +153,8 @@ We first need a view manager:
   >>> nodeChecker = NamesChecker(('body',))
   >>> defineChecker(Node, nodeChecker)
 
-  >>> loops['views'] = ViewManager()
-  >>> views = loops['views']
+  >>> loopsRoot['views'] = ViewManager()
+  >>> views = loopsRoot['views']
 
 The view space is typically built up with nodes; a node may be a top-level
 menu that may contain other nodes as menu or content items:
@@ -290,7 +314,6 @@ instance to another.
   >>> data[3]['name']
   u'm112'
 
-  >>> import os
   >>> dumpname = os.path.dirname(__file__) + '/test.tmp'
   >>> exporter.filename = dumpname
   >>> exporter.dumpData()
diff --git a/configure.zcml b/configure.zcml
index f136103..7403b9c 100644
--- a/configure.zcml
+++ b/configure.zcml
@@ -152,6 +152,12 @@
 
   </content>
 
+  <!--<adapter
+      factory="zope.app.file.image.ImageSized"
+      provides="zope.app.size.interfaces.ISized"
+      for=".interfaces.IMediaAsset"
+      />-->
+
   <!-- view manager and view -->
 
   <interface interface=".interfaces.IViewManager"
@@ -215,13 +221,11 @@
   
   <view factory="loops.view.NodeTraverser"
         for="loops.interfaces.INode"
-        type="zope.publisher.interfaces.http.IHTTPRequest"
-        provides="zope.publisher.interfaces.IPublishTraverse"
-        allowed_interface="zope.publisher.interfaces.IPublishTraverse"
+        type="zope.publisher.interfaces.browser.IBrowserRequest"
+        provides="zope.publisher.interfaces.browser.IBrowserPublisher"
+        allowed_interface="zope.publisher.interfaces.browser.IBrowserPublisher"
         permission="zope.Public" />
 
-  <!--<adapter factory="loops.view.NodeTraversable" />-->
-
   <!-- Register various browser related components, including all views -->
   <include package=".browser" />
 
diff --git a/interfaces.py b/interfaces.py
index 60e8a13..3191d02 100644
--- a/interfaces.py
+++ b/interfaces.py
@@ -108,14 +108,23 @@ class IResource(Interface):
 
     title = schema.TextLine(
                 title=_(u'Title'),
-                description=_(u'Title of the document'),
+                description=_(u'Title of the resource'),
+                default=u'',
+                missing_value=u'',
                 required=False)
 
-    contentType = schema.TextLine(
+    contentType = schema.BytesLine(
                 title=_(u'Content Type'),
-                description=_(u'Content type (format) of the body field, '
-                               'default is "text/xml"'),
-                default=_(u'text/xml'),
+                description=_(u'Content type (format) of the data field'),
+                default='',
+                missing_value='',
+                required=False)
+
+    data = schema.Bytes(
+                title=_(u'Data'),
+                description=_(u'Resource raw data'),
+                default='',
+                missing_value='',
                 required=False)
 
     def getClients(relationships=None):
@@ -131,6 +140,8 @@ class IDocument(IResource):
     data = schema.Text(
                 title=_(u'Data'),
                 description=_(u'Raw body data of the document'),
+                default=u'',
+                missing_value=u'',
                 required=False)
 
 
@@ -141,7 +152,9 @@ class IMediaAsset(IResource, IBaseAsset):
 
     data = schema.Bytes(
                 title=_(u'Data'),
-                description=_(u'Media asset raw data'),
+                description=_(u'Media asset file'),
+                default='',
+                missing_value='',
                 required=False)
 
 
diff --git a/resource.py b/resource.py
index 72ddede..8e5afaa 100644
--- a/resource.py
+++ b/resource.py
@@ -44,16 +44,11 @@ class Resource(Contained, Persistent):
     def setTitle(self, title): self._title = title
     title = property(getTitle, setTitle)
 
-    _contentType = u'text/xml'
+    _contentType = ''
     def setContentType(self, contentType): self._contentType = contentType
     def getContentType(self): return self._contentType
     contentType = property(getContentType, setContentType)
 
-    _data = u''
-    def setData(self, data): self._data = data
-    def getData(self): return self._data
-    data = property(getData, setData)
-
     def getClients(self, relationships=None):
         rels = getRelations(second=self, relationships=relationships)
         return [r.first for r in rels]
@@ -61,11 +56,18 @@ class Resource(Contained, Persistent):
     def __init__(self, title=u''):
         self.title = title
 
+    _size = 0
+
 
 class Document(Resource):
 
     implements(IDocument)
 
+    _data = u''
+    def setData(self, data): self._data = data
+    def getData(self): return self._data
+    data = property(getData, setData)
+
 
 class MediaAsset(Resource, BaseMediaAsset):
 
@@ -75,6 +77,17 @@ class MediaAsset(Resource, BaseMediaAsset):
         super(MediaAsset, self).__init__()
         self.title = title
 
+    def _setData(self, data):
+        super(MediaAsset, self)._setData(data)
+        if not self.contentType:
+            self.guessContentType(data)
+
+    data = property(BaseMediaAsset._getData, _setData)
+
+    def guessContentType(self, data):
+        if data.startswith('%PDF'):
+            self.contentType = 'application/pdf'
+
 
 class ResourceManager(BTreeContainer):
 
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..4bc90fb
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,4 @@
+"""
+$Id$
+"""
+
diff --git a/tests/test.pdf b/tests/test.pdf
new file mode 100644
index 0000000..b440416
Binary files /dev/null and b/tests/test.pdf differ
diff --git a/tests/test_icon.png b/tests/test_icon.png
new file mode 100644
index 0000000..4b84c9e
Binary files /dev/null and b/tests/test_icon.png differ
diff --git a/tests.py b/tests/test_loops.py
similarity index 85%
rename from tests.py
rename to tests/test_loops.py
index 784165b..503ec23 100755
--- a/tests.py
+++ b/tests/test_loops.py
@@ -8,11 +8,11 @@ from zope.interface import implements
 from zope.app import zapi
 from zope.app.intid.interfaces import IIntIds
 
-from interfaces import ILoops
+from loops.interfaces import ILoops
 from loops import Loops
-from interfaces import IConcept, IConceptManager
-from interfaces import IDocument, IMediaAsset, IResourceManager
-from interfaces import INode, IViewManager
+from loops.interfaces import IConcept, IConceptManager
+from loops.interfaces import IDocument, IMediaAsset, IResourceManager
+from loops.interfaces import INode, IViewManager
 from loops.concept import Concept, ConceptManager
 from loops.resource import Document, MediaAsset, ResourceManager
 from loops.view import Node, ViewManager
@@ -43,7 +43,7 @@ def test_suite():
     flags = doctest.NORMALIZE_WHITESPACE | doctest.ELLIPSIS
     return unittest.TestSuite((
                 unittest.makeSuite(Test),
-                DocFileSuite('README.txt', optionflags=flags),
+                DocFileSuite('../README.txt', optionflags=flags),
             ))
 
 if __name__ == '__main__':
diff --git a/view.py b/view.py
index 3551dde..6014819 100644
--- a/view.py
+++ b/view.py
@@ -159,15 +159,3 @@ class NodeTraverser(ItemTraverser):
             return self.context.getLoopsRoot()
         return super(NodeTraverser, self).publishTraverse(request, name)
  
- 
-# class NodeTraversable(ContainerTraversable):
-# 
-#     adapts(INode)
-# 
-#     def traverse(self, name, furtherPath):
-#         print name
-#         if str(name) == '.loops':
-#             print self._container.getLoopsRoot()
-#             return self._container.getLoopsRoot()
-#         return super(NodeTraversable, self).traverse(name, furtherPath)
-