diff --git a/git.py b/git.py
index 78f5b1e..9f73fd1 100644
--- a/git.py
+++ b/git.py
@@ -339,12 +339,12 @@ class Repo:
             ref = self.branch
         return Tree(self, ref)
 
-    def blob(self, path, ref = None, raw = False):
+    def blob(self, path, ref = None):
         """Returns a Blob instance for the given path."""
         if not ref:
             ref = self.branch
         cmd = self.cmd('cat-file')
-        cmd.raw(raw)
+        cmd.raw(True)
         cmd.batch = None
 
         if isinstance(ref, unicode):
@@ -356,7 +356,7 @@ class Repo:
         if not head or head.strip().endswith('missing'):
             return None
 
-        return Blob(out.read(), raw)
+        return Blob(out.read())
 
     def last_commit_timestamp(self):
         """Return the timestamp of the last commit."""
@@ -559,8 +559,12 @@ class Tree:
 class Blob:
     """A git blob."""
 
-    def __init__(self, content, raw):
-        if raw:
-            self.raw_content = content
-        else:
-            self.utf8_content = content
+    def __init__(self, raw_content):
+        self.raw_content = raw_content
+        self._utf8_content = None
+
+    @property
+    def utf8_content(self):
+        if not self._utf8_content:
+            self._utf8_content = self.raw_content.decode('utf8', 'replace')
+        return self._utf8_content
diff --git a/utils.py b/utils.py
index be6ab78..7223303 100644
--- a/utils.py
+++ b/utils.py
@@ -102,9 +102,9 @@ def embed_image_blob(repo, dirname, fname):
     mimetype = mimetypes.guess_type(fname)[0]
 
     # Unfortunately, bottle seems to require utf-8 encoded data.
-    # We have to refetch the blob with raw=True, because the utf-8 encoded
+    # We have to refetch the blob as raw data, because the utf-8 encoded
     # version of the blob available in the bottle template discards binary data.
-    raw_blob = repo.blob(dirname + fname, raw = True)
+    raw_blob = repo.blob(dirname + fname)
 
     return '<img style="max-width:100%;" src="data:{0};base64,{1}" />'.format( \
                                     mimetype, base64.b64encode(raw_blob.raw_content))