diff --git a/lib/compass/sass_extensions/sprites/base.rb b/lib/compass/sass_extensions/sprites/base.rb
index 112db850..a2e16f75 100644
--- a/lib/compass/sass_extensions/sprites/base.rb
+++ b/lib/compass/sass_extensions/sprites/base.rb
@@ -1,5 +1,3 @@
-require 'compass/sass_extensions/sprites/image'
-require 'compass/sass_extensions/sprites/engines/chunky_png_engine'
 module Compass
   module SassExtensions
     module Sprites
diff --git a/lib/compass/sass_extensions/sprites/engines.rb b/lib/compass/sass_extensions/sprites/engines.rb
new file mode 100644
index 00000000..26a73260
--- /dev/null
+++ b/lib/compass/sass_extensions/sprites/engines.rb
@@ -0,0 +1 @@
+require 'compass/sass_extensions/sprites/engines/chunky_png_engine'
\ No newline at end of file
diff --git a/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb b/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
index 3990cd45..1483b762 100644
--- a/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
+++ b/lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb
@@ -16,7 +16,7 @@ module Compass
           images.each do |image|
             input_png  = ChunkyPNG::Image.from_file(image.file)
             if image.repeat == "no-repeat"
-              output_png.replace input_png, image.left, image.top
+              output_png.replace! input_png, image.left, image.top
             else
               x = image.left - (image.left / image.width).ceil * image.width
               while x < width do
diff --git a/lib/compass/sass_extensions/sprites/image.rb b/lib/compass/sass_extensions/sprites/image.rb
index f90861e6..07c8cfdd 100644
--- a/lib/compass/sass_extensions/sprites/image.rb
+++ b/lib/compass/sass_extensions/sprites/image.rb
@@ -1,5 +1,3 @@
-require 'digest/md5'
-
 module Compass
   module SassExtensions
     module Sprites