Patch for 1.2.1

django/core/files/images.py

@@ -44,13 +44,18 @@ def get_image_dimensions(file_or_path):
         file = open(file_or_path, 'rb')
         close = True
     try:
+        # Most of the time PIL only needs a small chunk to parse the image and
+        # get the dimensions, but with some TIFF files PIL needs to parse the
+        # whole file.
+        chunk_size = 1024
         while 1:
-            data = file.read(1024)
+            data = file.read(chunk_size)
             if not data:
                 break
             p.feed(data)
             if p.image:
                 return p.image.size
+            chunk_size = chunk_size*2
         return None
     finally:
         if close:

django/core/files/images.py.orig

@@ -0,0 +1,57 @@
+"""
+Utility functions for handling images.
+
+Requires PIL, as you might imagine.
+"""
+
+from django.core.files import File
+
+class ImageFile(File):
+    """
+    A mixin for use alongside django.core.files.base.File, which provides
+    additional features for dealing with images.
+    """
+    def _get_width(self):
+        return self._get_image_dimensions()[0]
+    width = property(_get_width)
+
+    def _get_height(self):
+        return self._get_image_dimensions()[1]
+    height = property(_get_height)
+
+    def _get_image_dimensions(self):
+        if not hasattr(self, '_dimensions_cache'):
+            close = self.closed
+            self.open()
+            self._dimensions_cache = get_image_dimensions(self)
+            if close:
+                self.close()
+        return self._dimensions_cache
+
+def get_image_dimensions(file_or_path):
+    """Returns the (width, height) of an image, given an open file or a path."""
+    # Try to import PIL in either of the two ways it can end up installed.
+    try:
+        from PIL import ImageFile as PILImageFile
+    except ImportError:
+        import ImageFile as PILImageFile
+
+    p = PILImageFile.Parser()
+    close = False
+    if hasattr(file_or_path, 'read'):
+        file = file_or_path
+    else:
+        file = open(file_or_path, 'rb')
+        close = True
+    try:
+        while 1:
+            data = file.read(1024)
+            if not data:
+                break
+            p.feed(data)
+            if p.image:
+                return p.image.size
+        return None
+    finally:
+        if close:
+            file.close()