FIX: don't try to optimize large PNGs (takes too much time)

app/models/upload.rb

@@ -73,8 +73,8 @@ class Upload < ActiveRecord::Base
           w = svg["width"].to_i
           h = svg["height"].to_i
         else
-          # fix orientation first (but not for GIFs)
-          fix_image_orientation(file.path) unless filename =~ /\.GIF$/i
+          # fix orientation first
+          fix_image_orientation(file.path) if should_optimize?(file.path)
           # retrieve image info
           image_info = FastImage.new(file) rescue nil
           w, h = *(image_info.try(:size) || [0, 0])
@@ -107,8 +107,8 @@ class Upload < ActiveRecord::Base
           end
         end
 
-        # optimize image (but not for GIFs)
-        if filename !~ /\.GIF$/i
+        # optimize image (except GIFs and large PNGs)
+        if should_optimize?(file.path)
           ImageOptim.new.optimize_image!(file.path) rescue nil
           # update the file size
           filesize = File.size(file.path)
@@ -163,6 +163,18 @@ class Upload < ActiveRecord::Base
     end
   end
 
+  LARGE_PNG_SIZE ||= 3.megabytes
+
+  def self.should_optimize?(path)
+    # don't optimize GIFs
+    return false if path =~ /\.gif$/i
+    return true  if path !~ /\.png$/i
+    image_info = FastImage.new(path) rescue nil
+    w, h = *(image_info.try(:size) || [0, 0])
+    # don't optimize large PNGs
+    w > 0 && h > 0 && w * h < LARGE_PNG_SIZE
+  end
+
   def self.is_dimensionless_image?(filename, width, height)
     FileHelper.is_image?(filename) && (width.blank? || width == 0 || height.blank? || height == 0)
   end