diff --git a/app/models/upload.rb b/app/models/upload.rb
index cf95ec5aa28..d6119abc13c 100644
--- a/app/models/upload.rb
+++ b/app/models/upload.rb
@@ -95,6 +95,8 @@ class Upload < ActiveRecord::Base
   #   - image_type ("avatar", "profile_background", "card_background")
   #   - is_attachment_for_group_message (boolean)
   def self.create_for(user_id, file, filename, filesize, options = {})
+    upload = Upload.new
+
     DistributedMutex.synchronize("upload_#{user_id}_#{filename}") do
       # do some work on images
       if FileHelper.is_image?(filename) && is_actual_image?(file)
@@ -105,13 +107,19 @@ class Upload < ActiveRecord::Base
           File.write(file.path, doc.to_s)
           file.rewind
         else
+          # ensure image isn't huge
+          w, h = FastImage.size(file) || [0, 0]
+          if w * h >= SiteSetting.max_image_megapixels * 1_000_000
+            upload.errors.add(:base, I18n.t("upload.images.larger_than_x_megapixels", max_image_megapixels: SiteSetting.max_image_megapixels))
+            return upload
+          end
+
           # fix orientation first
           fix_image_orientation(file.path) if should_optimize?(file.path)
         end
 
         # retrieve image info
-        image_info = FastImage.new(file)
-        w, h = *(image_info.try(:size) || [0, 0])
+        w, h = FastImage.size(file) || [0, 0]
 
         # default size
         width, height = ImageSizer.resize(w, h)
@@ -214,8 +222,7 @@ class Upload < ActiveRecord::Base
     # don't optimize GIFs or SVGs
     return false if path =~ /\.(gif|svg)$/i
     return true  if path !~ /\.png$/i
-    image_info = FastImage.new(path) rescue nil
-    w, h = *(image_info.try(:size) || [0, 0])
+    w, h = FastImage.size(path) || [0, 0]
     # don't optimize large PNGs
     w > 0 && h > 0 && w * h < LARGE_PNG_SIZE
   end
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 808beed3794..6468a337a07 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1213,6 +1213,8 @@ en:
     authorized_extensions: "A list of file extensions allowed for upload (use '*' to enable all file types)"
     max_similar_results: "How many similar topics to show above the editor when composing a new topic. Comparison is based on title and body."
 
+    max_image_megapixels: "Maximum number of megapixels allowed for an image."
+
     title_prettify: "Prevent common title typos and errors, including all caps, lowercase first character, multiple ! and ?, extra . at end, etc."
 
     topic_views_heat_low: "After this many views, the views field is slightly highlighted."
@@ -2640,6 +2642,7 @@ en:
       too_large: "Sorry, the file you are trying to upload is too big (maximum size is %{max_size_kb}KB)."
     images:
       too_large: "Sorry, the image you are trying to upload is too big (maximum size is %{max_size_kb}KB), please resize it and try again."
+      larger_than_x_megapixels: "Sorry, the image you are trying to upload is too large (maximum dimension is %{max_image_megapixels}-megapixels), please resize it and try again."
       size_not_found: "Sorry, but we couldn't determine the size of the image. Maybe your image is corrupted?"
 
   avatar:
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 4344fab89e5..ae668d64e45 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -699,6 +699,10 @@ files:
   max_attachment_size_kb:
     client: true
     default: 3072
+  max_image_megapixels:
+    default: 40
+    min: 5
+    max: 100
   authorized_extensions:
     client: true
     default: 'jpg|jpeg|png|gif'
diff --git a/spec/fixtures/images/huge.jpg b/spec/fixtures/images/huge.jpg
new file mode 100644
index 00000000000..25f2d5c6fb4
Binary files /dev/null and b/spec/fixtures/images/huge.jpg differ
diff --git a/spec/models/upload_spec.rb b/spec/models/upload_spec.rb
index 6412be89428..4cf0ad64e05 100644
--- a/spec/models/upload_spec.rb
+++ b/spec/models/upload_spec.rb
@@ -17,6 +17,10 @@ describe Upload do
   let(:image_svg) { file_from_fixtures(image_svg_filename) }
   let(:image_svg_filesize) { File.size(image_svg) }
 
+  let(:huge_image_filename) { "huge.jpg" }
+  let(:huge_image) { file_from_fixtures(huge_image_filename) }
+  let(:huge_image_filesize) { File.size(huge_image) }
+
   let(:attachment_path) { __FILE__ }
   let(:attachment) { File.new(attachment_path) }
   let(:attachment_filename) { File.basename(attachment_path) }
@@ -55,6 +59,12 @@ describe Upload do
       expect(Upload.create_for(user_id, image, image_filename, image_filesize)).to eq(upload)
     end
 
+    it "ensures images isn't huge before processing it" do
+      Upload.expects(:fix_image_orientation).never
+      upload = Upload.create_for(user_id, huge_image, huge_image_filename, huge_image_filesize)
+      expect(upload.errors.size).to be > 0
+    end
+
     it "fix image orientation" do
       Upload.expects(:fix_image_orientation).with(image.path)
       Upload.create_for(user_id, image, image_filename, image_filesize)
@@ -62,7 +72,6 @@ describe Upload do
 
     it "computes width & height for images" do
       ImageSizer.expects(:resize)
-      image.expects(:rewind).times(3)
       Upload.create_for(user_id, image, image_filename, image_filesize)
     end