diff --git a/app/views/settings/_display.html.erb b/app/views/settings/_display.html.erb
index 30e6525f7..17c4ed817 100644
--- a/app/views/settings/_display.html.erb
+++ b/app/views/settings/_display.html.erb
@@ -28,6 +28,8 @@
 
 <p><%= setting_text_field :thumbnails_size, :size => 6 %></p>
 
+<p><%= setting_text_field :thumbnails_timeout, :size => 6 %></p>
+
 <p><%= setting_select :new_item_menu_tab, [[l(:label_none), '0'], [l(:label_new_project_issue_tab_enabled), '1'], [l(:label_new_object_tab_enabled), '2']] %></p>
 </div>
 
diff --git a/config/locales/en.yml b/config/locales/en.yml
index c842e4d7b..3c83c6176 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -494,6 +494,7 @@ en:
   setting_session_timeout: Session inactivity timeout
   setting_thumbnails_enabled: Display attachment thumbnails
   setting_thumbnails_size: Thumbnails size (in pixels)
+  setting_thumbnails_timeout: Thumbnails creation timeout (in seconds)
   setting_non_working_week_days: Non-working days
   setting_jsonp_enabled: Enable JSONP support
   setting_default_projects_tracker_ids: Default trackers for new projects
diff --git a/config/settings.yml b/config/settings.yml
index bd3795756..798146f24 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -325,6 +325,9 @@ thumbnails_enabled:
 thumbnails_size:
   format: int
   default: 100
+thumbnails_timeout:
+  format: int
+  default: 10
 non_working_week_days:
   serialized: true
   default:
diff --git a/lib/redmine/thumbnail.rb b/lib/redmine/thumbnail.rb
index 4c886a5b3..bf18fead5 100644
--- a/lib/redmine/thumbnail.rb
+++ b/lib/redmine/thumbnail.rb
@@ -18,6 +18,7 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 
 require 'fileutils'
+require 'timeout'
 
 module Redmine
   module Thumbnail
@@ -51,8 +52,25 @@ module Redmine
         else
           cmd = "#{shell_quote CONVERT_BIN} #{shell_quote source} -auto-orient -thumbnail #{shell_quote size_option} #{shell_quote target}"
         end
-        unless system(cmd)
-          logger.error("Creating thumbnail failed (#{$?}):\nCommand: #{cmd}")
+
+        pid = nil
+        begin
+          Timeout.timeout(Setting.thumbnails_timeout.to_i) do
+            pid = Process.spawn(cmd)
+            _, status = Process.wait2(pid)
+            unless status.success?
+              logger.error("Creating thumbnail failed (#{status.exitstatus}):\nCommand: #{cmd}")
+              return nil
+            end
+          end
+        rescue Timeout::Error
+          begin
+            Process.kill('TERM', pid)
+            Timeout.timeout(1) { Process.wait(pid) }
+          rescue Timeout::Error
+            Process.kill('KILL', pid)
+          end
+          logger.error("Creating thumbnail timed out:\nCommand: #{cmd}")
           return nil
         end
       end
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
index 2e37672ab..b88350fba 100644
--- a/test/unit/attachment_test.rb
+++ b/test/unit/attachment_test.rb
@@ -626,6 +626,25 @@ class AttachmentTest < ActiveSupport::TestCase
     ensure
       set_tmp_attachments_directory
     end
+
+    def test_thumbnail_should_timeout
+      dummy_pid = 37530
+      Process.stubs(:spawn).returns(dummy_pid)
+      Process.stubs(:wait2).raises(Timeout::Error)
+      Process.stubs(:kill).returns(1)
+      Process.stubs(:wait).returns(dummy_pid)
+      Rails.logger.expects(:error).with(regexp_matches(/Creating thumbnail timed out/))
+
+      set_fixtures_attachments_directory
+      Attachment.clear_thumbnails
+
+      attachment = Attachment.find(16)
+      thumbnail = attachment.thumbnail
+
+      assert_nil thumbnail
+    ensure
+      set_tmp_attachments_directory
+    end
   else
     puts '(ImageMagick convert not available)'
   end