diff --git a/lib/compass/sass_extensions/functions/image_size.rb b/lib/compass/sass_extensions/functions/image_size.rb
index 453010bc..864b8cdc 100644
--- a/lib/compass/sass_extensions/functions/image_size.rb
+++ b/lib/compass/sass_extensions/functions/image_size.rb
@@ -1,10 +1,12 @@
 module Compass::SassExtensions::Functions::ImageSize
+  # Returns the width of the image relative to the images directory
   def image_width(image_file)
     image_path = real_path(image_file)
     width = ImageProperties.new(image_path).size.first
     Sass::Script::Number.new(width,["px"])
   end
 
+  # Returns the height of the image relative to the images directory
   def image_height(image_file)
     image_path = real_path(image_file)
     height = ImageProperties.new(image_path).size.last
@@ -15,8 +17,8 @@ private
   def real_path(image_file)
     path = image_file.value
     # Compute the real path to the image on the file stystem if the images_dir is set.
-    if Compass.configuration.images_dir
-      File.join(Compass.configuration.project_path, Compass.configuration.images_dir, path)
+    if Compass.configuration.images_path
+      File.join(Compass.configuration.images_path, path)
     else
       File.join(Compass.configuration.project_path, path)
     end
@@ -29,7 +31,9 @@ private
     end
 
     def size
-      @dimensions ||=  send("get_size_for_#{@file_type}")
+      @dimensions ||= send(:"get_size_for_#{@file_type}")
+    rescue NoMethodError
+      raise Sass::SyntaxError, "Unrecognized file type: #{@file_type}"
     end
 
   private
@@ -39,12 +43,6 @@ private
 
     def get_size_for_gif
       size = IO.read(@file)[6..10].unpack('SS')
-      size.inspect
-    end
-
-    def get_size_for_bmp
-      d = IO.read(@file)[14..28]
-      d[0] == 40 ? d[4..-1].unpack('LL') : d[4..8].unpack('SS')
     end
 
     def get_size_for_jpg
diff --git a/test/compass_test.rb b/test/compass_test.rb
index d0e43f23..665d0070 100644
--- a/test/compass_test.rb
+++ b/test/compass_test.rb
@@ -42,7 +42,7 @@ class CompassTest < Test::Unit::TestCase
       each_css_file(proj.css_path) do |css_file|
         assert_no_errors css_file, 'compass'
       end
-      assert_renders_correctly :reset, :layout, :utilities, :gradients
+      assert_renders_correctly :reset, :layout, :utilities, :gradients, :image_size
     end
   end
 
diff --git a/test/fixtures/stylesheets/compass/100x150.jpg b/test/fixtures/stylesheets/compass/100x150.jpg
new file mode 100644
index 00000000..70771213
Binary files /dev/null and b/test/fixtures/stylesheets/compass/100x150.jpg differ
diff --git a/test/fixtures/stylesheets/compass/css/image_size.css b/test/fixtures/stylesheets/compass/css/image_size.css
new file mode 100644
index 00000000..e74a195d
--- /dev/null
+++ b/test/fixtures/stylesheets/compass/css/image_size.css
@@ -0,0 +1,15 @@
+.png {
+  width: 100px;
+  height: 150px; }
+
+.jpg {
+  width: 100px;
+  height: 150px; }
+
+.jpeg {
+  width: 100px;
+  height: 150px; }
+
+.gif {
+  width: 100px;
+  height: 150px; }
diff --git a/test/fixtures/stylesheets/compass/images/100x150.gif b/test/fixtures/stylesheets/compass/images/100x150.gif
new file mode 100644
index 00000000..b0368594
Binary files /dev/null and b/test/fixtures/stylesheets/compass/images/100x150.gif differ
diff --git a/test/fixtures/stylesheets/compass/images/100x150.jpeg b/test/fixtures/stylesheets/compass/images/100x150.jpeg
new file mode 100644
index 00000000..70771213
Binary files /dev/null and b/test/fixtures/stylesheets/compass/images/100x150.jpeg differ
diff --git a/test/fixtures/stylesheets/compass/images/100x150.jpg b/test/fixtures/stylesheets/compass/images/100x150.jpg
new file mode 100644
index 00000000..70771213
Binary files /dev/null and b/test/fixtures/stylesheets/compass/images/100x150.jpg differ
diff --git a/test/fixtures/stylesheets/compass/images/100x150.png b/test/fixtures/stylesheets/compass/images/100x150.png
new file mode 100644
index 00000000..5cec428d
Binary files /dev/null and b/test/fixtures/stylesheets/compass/images/100x150.png differ
diff --git a/test/fixtures/stylesheets/compass/sass/image_size.sass b/test/fixtures/stylesheets/compass/sass/image_size.sass
new file mode 100644
index 00000000..982fceee
--- /dev/null
+++ b/test/fixtures/stylesheets/compass/sass/image_size.sass
@@ -0,0 +1,12 @@
+.png
+  width= image_width("100x150.png")
+  height= image_height("100x150.png")
+.jpg
+  width= image_width("100x150.jpg")
+  height= image_height("100x150.jpg")
+.jpeg
+  width= image_width("100x150.jpeg")
+  height= image_height("100x150.jpeg")
+.gif
+  width= image_width("100x150.gif")
+  height= image_height("100x150.gif")