FEATURE: new 'strip image metadata' site setting

.image_optim.yml

@@ -1,12 +0,0 @@
-skip_missing_workers: true
-allow_lossy: false
-# PNG
-advpng: false
-optipng:
-  level: 2
-pngcrush: false
-pngout: false
-pngquant: false
-# JPG
-jpegrecompress: false
-timeout: 15

app/models/optimized_image.rb

@@ -107,6 +107,9 @@ class OptimizedImage < ActiveRecord::Base
     end
   end
 
+  def self.thumbnail_or_resize
+    SiteSetting.strip_image_metadata ? "thumbnail" : "resize"
+  end
 
   def self.resize_instructions(from, to, dimensions, opts={})
     ensure_safe_paths!(from, to)
@@ -118,7 +121,7 @@ class OptimizedImage < ActiveRecord::Base
       -auto-orient
       -gravity center
       -background transparent
-      -thumbnail #{dimensions}^
+      -#{thumbnail_or_resize} #{dimensions}^
       -extent #{dimensions}
       -interpolate bicubic
       -unsharp 2x0.5+0.7+0
@@ -151,7 +154,7 @@ class OptimizedImage < ActiveRecord::Base
       -auto-orient
       -gravity north
       -background transparent
-      -thumbnail #{opts[:width]}
+      -#{thumbnail_or_resize} #{opts[:width]}
       -crop #{dimensions}+0+0
       -unsharp 2x0.5+0.7+0
       -interlace none
@@ -223,7 +226,7 @@ class OptimizedImage < ActiveRecord::Base
       return false
     end
 
-    ImageOptim.new.optimize_image!(to)
+    FileHelper.optimize_image!(to)
     true
   rescue
     Rails.logger.error("Could not optimize image: #{to}")
@@ -268,7 +271,7 @@ class OptimizedImage < ActiveRecord::Base
             optimized_image.sha1 = Upload.generate_digest(path)
           end
           # optimize if image
-          ImageOptim.new.optimize_image!(path)
+          FileHelper.optimize_image!(path)
           # store to new location & update the filesize
           File.open(path) do |f|
             optimized_image.url = Discourse.store.store_optimized_image(f, optimized_image)

app/models/upload.rb

@@ -109,9 +109,7 @@ class Upload < ActiveRecord::Base
             upload.sha1 = Upload.generate_digest(path)
           end
           # optimize if image
-          if FileHelper.is_image?(File.basename(path))
-            ImageOptim.new.optimize_image!(path)
-          end
+          FileHelper.optimize_image!(path) if FileHelper.is_image?(File.basename(path))
           # store to new location & update the filesize
           File.open(path) do |f|
             upload.url = Discourse.store.store_upload(f, upload)

config/locales/server.en.yml

@@ -1206,6 +1206,8 @@ en:
 
     allow_staff_to_upload_any_file_in_pm: "Allow staff members to upload any files in PM."
 
+    strip_image_metadata: "Strip image metadata."
+
     enable_flash_video_onebox: "Enable embedding of swf and flv (Adobe Flash) links in oneboxes. WARNING: may introduce security risks."
 
     default_invitee_trust_level: "Default trust level (0-4) for invited users."

config/site_settings.yml

@@ -811,6 +811,7 @@ files:
   allow_staff_to_upload_any_file_in_pm:
     default: true
     client: true
+  strip_image_metadata: true
 
 trust:
   default_trust_level:

lib/file_helper.rb

@@ -48,14 +48,32 @@ class FileHelper
     downloaded&.close
   end
 
+  def self.optimize_image!(filename)
+    ImageOptim.new(
+      # GLOBAL
+      timeout: 15,
+      skip_missing_workers: true,
+      # PNG
+      optipng: { level: 2, strip: SiteSetting.strip_image_metadata },
+      advpng: false,
+      pngcrush: false,
+      pngout: false,
+      pngquant: false,
+      # JPG
+      jpegoptim: { strip: SiteSetting.strip_image_metadata ? "all" : "none" },
+      jpegtran: false,
+      jpegrecompress: false,
+    ).optimize_image!(filename)
+  end
+
   private
 
-  def self.images
-    @@images ||= Set.new %w{jpg jpeg png gif tif tiff bmp svg webp ico}
-  end
+    def self.images
+      @@images ||= Set.new %w{jpg jpeg png gif tif tiff bmp svg webp ico}
+    end
 
-  def self.images_regexp
-    @@images_regexp ||= /\.(#{images.to_a.join("|")})$/i
-  end
+    def self.images_regexp
+      @@images_regexp ||= /\.(#{images.to_a.join("|")})$/i
+    end
 
 end

lib/tasks/images.rake

@@ -1,8 +1,9 @@
+require_dependency "file_helper"
+
 task "images:compress" => :environment do
-  io = ImageOptim.new
   images = Dir.glob("#{Rails.root}/app/**/*.png")
   image_sizes = Hash[*images.map{|i| [i,File.size(i)]}.to_a.flatten]
-  io.optimize_images!(images) do |name, optimized|
+  FileHelper.optimize_images!(images) do |name, optimized|
     if optimized
       new_size = File.size(name)
       puts "#{name} => from: #{image_sizes[name.to_s]} to: #{new_size}"

lib/upload_creator.rb

@@ -237,7 +237,7 @@ class UploadCreator
 
   def optimize!
     OptimizedImage.ensure_safe_paths!(@file.path)
-    ImageOptim.new.optimize_image!(@file.path)
+    FileHelper.optimize_image!(@file.path)
     extract_image_info!
   rescue ImageOptim::Worker::TimeoutExceeded
     Rails.logger.warn("ImageOptim timed out while optimizing #{@filename}")