diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index bc5f925..78ff31c 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -1,7 +1,7 @@
 # -*- encoding : utf-8 -*-
 require 'kramdown'
 require 'digest/md5'
-require 'uri'
+require 'cgi'
 
 module ApplicationHelper
 
@@ -58,20 +58,19 @@ def gravatar_image(user, options = {})
     return nil if user.nil? || user.email.nil?
 
     hash = Digest::MD5.hexdigest(user.email.downcase)
-    query = options.select { |k, v| [:size, :default].include?(k) }
-                   .map { |k, v| "#{k}=#{URI.encode(v.to_s)}" }
-                   .join('&')
-    src = "//www.gravatar.com/avatar/#{hash}?#{query}"
-
-    img_options = { :alt => user.nickname }
-    if mouseover = options[:mouseover]
-      img_options[:mouseover] = mouseover
-    end
+    opts = options.dup
+    query = opts.select { |k, v| [:size, :d].include?(k) }
+                .map { |k, v| "#{k}=#{CGI.escape(v.to_s)}" }
+                .join('&')
+    img_options = {
+      :src => "//www.gravatar.com/avatar/#{hash}?#{query}",
+      :alt => user.nickname
+    }
     if size = options[:size]
       img_options[:width] = size
       img_options[:height] = size
     end
 
-    image_tag(src, img_options)
+    tag 'img', img_options, false, false
   end
 end
diff --git a/spec/helpers/application_helper_spec.rb b/spec/helpers/application_helper_spec.rb
index 5fd9273..d2568c4 100644
--- a/spec/helpers/application_helper_spec.rb
+++ b/spec/helpers/application_helper_spec.rb
@@ -114,5 +114,22 @@ def current_user
     end
   end
 
+  describe 'gravatar_image' do
+    it 'returns nil for user without email' do
+      u = create(:user, :email => nil)
+      result = gravatar_image(u)
+      expect(result).to be_nil
+    end
 
+    it 'works' do
+      u = create(:user, :nickname => 'Foo', :email => 'foo@bar.com')
+      options = {
+        :size => 25,
+        :d => 'http://test.com/default.jpg'
+      }
+      result = gravatar_image(u, options)
+      expected = '<img alt="Foo" height="25" src="//www.gravatar.com/avatar/f3ada405ce890b6f8204094deb12d8a8?size=25&d=http%3A%2F%2Ftest.com%2Fdefault.jpg" width="25" />'
+      expect(result).to eq(expected)
+    end
+  end
 end