diff --git a/lib/cooked_post_processor.rb b/lib/cooked_post_processor.rb
index 8ce16d2c5aa..62f268bcaa6 100644
--- a/lib/cooked_post_processor.rb
+++ b/lib/cooked_post_processor.rb
@@ -70,11 +70,22 @@ class CookedPostProcessor
   end
 
   def limit_size!(img)
-    w, h = get_size_from_image_sizes(img["src"], @opts[:image_sizes]) || get_size(img["src"])
+    # retrieve the size from
+    #  1) the width/height attributes
+    #  2) the dimension from the preview (image_sizes)
+    #  3) the dimension of the original image (HTTP request)
+    w, h = get_size_from_attributes(img) ||
+           get_size_from_image_sizes(img["src"], @opts[:image_sizes]) ||
+           get_size(img["src"])
     # limit the size of the thumbnail
     img["width"], img["height"] = ImageSizer.resize(w, h)
   end
 
+  def get_size_from_attributes(img)
+    w, h = img["width"].to_i, img["height"].to_i
+    return [w, h] if w > 0 && h > 0
+  end
+
   def get_size_from_image_sizes(src, image_sizes)
     return unless image_sizes.present?
     image_sizes.each do |image_size|
diff --git a/spec/components/cooked_post_processor_spec.rb b/spec/components/cooked_post_processor_spec.rb
index 08a070214ca..02cc21f28f5 100644
--- a/spec/components/cooked_post_processor_spec.rb
+++ b/spec/components/cooked_post_processor_spec.rb
@@ -42,12 +42,20 @@ describe CookedPostProcessor do
 
     context "with image_sizes" do
 
-      let(:post) { build(:post_with_image_url) }
+      let(:post) { build(:post_with_image_urls) }
       let(:cpp) { CookedPostProcessor.new(post, image_sizes: {"http://foo.bar/image.png" => {"width" => 111, "height" => 222}}) }
 
+      before { cpp.post_process_images }
+
+      it "adds the width from the image sizes provided when no dimension is provided" do
+        cpp.html.should =~ /src="http:\/\/foo.bar\/image.png" width="111" height="222"/
+      end
+
       it "adds the width from the image sizes provided" do
-        cpp.post_process_images
-        cpp.html.should =~ /width=\"111\"/
+        cpp.html.should =~ /src="http:\/\/domain.com\/picture.jpg" width="50" height="42"/
+      end
+
+      it "should be dirty" do
         cpp.should be_dirty
       end
 
diff --git a/spec/fabricators/post_fabricator.rb b/spec/fabricators/post_fabricator.rb
index c34e1c5f534..c8e116e62f4 100644
--- a/spec/fabricators/post_fabricator.rb
+++ b/spec/fabricators/post_fabricator.rb
@@ -58,8 +58,11 @@ Fabricator(:post_with_unsized_images, from: :post) do
 '
 end
 
-Fabricator(:post_with_image_url, from: :post) do
-  cooked '<img src="http://foo.bar/image.png" width="50" height="42">'
+Fabricator(:post_with_image_urls, from: :post) do
+  cooked '
+<img src="http://foo.bar/image.png">
+<img src="http://domain.com/picture.jpg" width="50" height="42">
+'
 end
 
 Fabricator(:post_with_large_image, from: :post) do