diff --git a/lib/watir-get-image-content/image.rb b/lib/watir-get-image-content/image.rb
index ebff8dc..53a8bdd 100644
--- a/lib/watir-get-image-content/image.rb
+++ b/lib/watir-get-image-content/image.rb
@@ -7,13 +7,13 @@ class Image
     def to_x_base64(target)
       assert_exists
       js = %Q{var canvas = document.createElement("canvas");
-              canvas.width = arguments[0].width;
-              canvas.height = arguments[0].height;
+              canvas.width = arguments[1];
+              canvas.height = arguments[2];
               var ctx = canvas.getContext("2d");
               ctx.drawImage(arguments[0], 0, 0);
               var dataURL = canvas.toDataURL("image/#{target}");
               return dataURL.replace(/^data:image\\/(png|jpg|gif);base64,/, "");}
-      driver.execute_script js, @element
+      driver.execute_script js, @element, naturalwidth, naturalheight
     end
 
     def to_png_base64
diff --git a/spec/matchers/image_similarity.rb b/spec/matchers/image_similarity.rb
new file mode 100644
index 0000000..b603ad1
--- /dev/null
+++ b/spec/matchers/image_similarity.rb
@@ -0,0 +1,36 @@
+module ImageSimilarity
+  RSpec::Matchers.define :be_similar_to do |dst|
+    match do |src|
+      base64_re = %r{^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}=+)$}
+
+      src_img, dst_img = [src, dst].map do |data|
+        if src =~ base64_re
+          Magick::Image.read_inline(src)
+        elsif (File.exist?(src) rescue nil)
+          Magick::Image.read(src)
+        else
+          tmp = Tempfile.new
+          tmp.write(src)
+          tmp.flush
+          begin
+            Magick::Image.read(tmp.path)
+          ensure
+            tmp.close
+            tmp.unlink
+          end
+        end
+      end
+
+      @diff_img, @diff_metric = src_img[0].compare_channel(dst_img[0], Magick::MeanSquaredErrorMetric)
+      @diff_metric <= @mse.to_f
+    end
+
+    chain :with_mse_less_then do |mse|
+      @mse = mse
+    end
+
+    failure_message do |actual|
+      "expected that mse #{@diff_metric} would be less or equal #{@mse.to_f}"
+    end
+  end
+end
diff --git a/spec/matchers/image_size.rb b/spec/matchers/image_size.rb
new file mode 100644
index 0000000..c8662a6
--- /dev/null
+++ b/spec/matchers/image_size.rb
@@ -0,0 +1,33 @@
+module ImageSize
+  RSpec::Matchers.define :be_same_size_as do |dst|
+    match do |src|
+      base64_re = %r{^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}=+)$}
+
+      src_img, dst_img = [src, dst].map do |data|
+        if src =~ base64_re
+          Magick::Image.read_inline(src)
+        elsif (File.exist?(src) rescue nil)
+          Magick::Image.read(src)
+        else
+          tmp = Tempfile.new
+          tmp.write(src)
+          tmp.flush
+          begin
+            Magick::Image.read(tmp.path)
+          ensure
+            tmp.close
+            tmp.unlink
+          end
+        end
+      end
+
+      @src_width, @src_height = src_img[0].columns, src_img[0].rows
+      @dst_width, @dst_height = dst_img[0].columns, dst_img[0].rows
+      @src_width == @dst_width && @src_height == @dst_height
+    end
+
+    failure_message do |actual|
+      "expected that size of src image (#{@src_width},#{@src_height}) would be same as of dst image (#{@dst_width},#{@dst_height})"
+    end
+  end
+end
diff --git a/spec/spec.html b/spec/spec.html
index a2e50ad..31cef2f 100644
--- a/spec/spec.html
+++ b/spec/spec.html
@@ -5,5 +5,9 @@
 <img src="./images/gif.gif" alt="gif"/>
 <img src="./images/jpg.jpg" alt="jpg"/>
 <img src="./images/png.png" alt="png"/>
+<br/>
+<img src="./images/gif.gif" width="260px" height="260px" alt="gif2"/>
+<img src="./images/jpg.jpg" width="260px" height="260px" alt="jpg2"/>
+<img src="./images/png.png" width="260px" height="260px" alt="png2"/>
 </body>
 </html>
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 560a031..c377909 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -2,6 +2,8 @@
 require 'rspec/expectations'
 require 'watir-get-image-content'
 require 'rbconfig'
+require 'matchers/image_similarity'
+require 'matchers/image_size'
 
 if RbConfig::CONFIG['host_os'] =~ /linux/
   dir = '/usr/lib/chromium-browser/'
@@ -16,14 +18,17 @@
 FileUtils.mkdir_p(tmp)
 
 RSpec.configure do |spec|
+  include ImageSimilarity
+  include ImageSize
+
   spec.before(:all) do
     caps = Selenium::WebDriver::Remote::Capabilities.chrome
-    args =['--disable-notifications',
-           '--unsafely-treat-insecure-origin-as-secure',
-           '--disable-web-security',
-           '--allow-file-access',
-           '--allow-file-access-from-files',
-           "--user-data-dir=#{tmp}"]
+    args = ['--disable-notifications',
+            '--unsafely-treat-insecure-origin-as-secure',
+            '--disable-web-security',
+            '--allow-file-access',
+            '--allow-file-access-from-files',
+            "--user-data-dir=#{tmp}"]
     @browser = Watir::Browser.new :chrome, desired_capabilities: caps, args: args
     @browser.goto "file://#{Dir.pwd}/spec/spec.html"
   end
@@ -36,37 +41,3 @@
     @browser.refresh
   end
 end
-
-RSpec::Matchers.define :be_similar_to do |dst|
-  match do |src|
-    base64_re = %r{^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}=+)$}
-    src_img, dst_img = [src, dst].map do |data|
-      if src =~ base64_re
-        Magick::Image.read_inline(src)
-      elsif (File.exist?(src) rescue nil)
-        Magick::Image.read(src)
-      else
-        tmp = Tempfile.new
-        tmp.write(src)
-        tmp.flush
-        begin
-          Magick::Image.read(tmp.path)
-        ensure
-          tmp.close
-          tmp.unlink
-        end
-      end
-    end
-
-    @diff_img, @diff_metric = src_img[0].compare_channel(dst_img[0], Magick::MeanSquaredErrorMetric)
-    @diff_metric <= @mse.to_f
-  end
-
-  chain :with_mse_less_then do |mse|
-    @mse = mse
-  end
-
-  failure_message do |actual|
-    "expected that mse #{@diff_metric} would be less or equal #{@mse.to_f}"
-  end
-end
diff --git a/spec/watir-get-image-content_spec.rb b/spec/watir-get-image-content_spec.rb
index 3188865..3f94676 100644
--- a/spec/watir-get-image-content_spec.rb
+++ b/spec/watir-get-image-content_spec.rb
@@ -2,50 +2,49 @@
 
 describe 'watir-get-image-content' do
   describe '#to_png_base64' do
-    it 'from png' do
-      expect(@browser.image(:alt, 'png').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png))
-    end
-
-    it 'from gif' do
-      expect(@browser.image(:alt, 'gif').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif))
+    describe 'original size' do
+      it { expect(@browser.image(:alt, 'png').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png)) }
+      it { expect(@browser.image(:alt, 'gif').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif)) }
+      it { expect(@browser.image(:alt, 'jpg').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001) }
     end
 
-    it 'from jpg' do
-      expect(@browser.image(:alt, 'jpg').to_png_base64).
-          to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001)
-    end
-  end
-
-  describe '#to_png' do
-    it 'from png' do
-      expect(@browser.image(:alt, 'png').to_png).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png))
-    end
+    describe 'resized' do
+      it { expect(@browser.image(:alt, 'png2').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png)) }
+      it { expect(@browser.image(:alt, 'png2').to_png_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images png.png)) }
 
-    it 'from gif' do
-      expect(@browser.image(:alt, 'gif').to_png).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif))
-    end
+      it { expect(@browser.image(:alt, 'gif2').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif)) }
+      it { expect(@browser.image(:alt, 'gif2').to_png_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images gif.gif)) }
 
-    it 'from jpg' do
-      expect(@browser.image(:alt, 'jpg').to_png).
-          to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001)
+      it { expect(@browser.image(:alt, 'jpg2').to_png_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001) }
+      it { expect(@browser.image(:alt, 'jpg2').to_png_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images jpg.jpg)) }
     end
   end
 
   describe '#to_jpg_base64' do
-    it 'from png' do
-      expect(@browser.image(:alt, 'png').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png))
+    describe 'original size' do
+      it { expect(@browser.image(:alt, 'png').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png)) }
+      it { expect(@browser.image(:alt, 'gif').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif)) }
+      it { expect(@browser.image(:alt, 'jpg').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001) }
     end
 
-    it 'from gif' do
-      expect(@browser.image(:alt, 'gif').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif))
-    end
+    describe 'resized' do
+      it { expect(@browser.image(:alt, 'png').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png)) }
+      it { expect(@browser.image(:alt, 'png').to_jpg_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images png.png)) }
 
-    it 'from jpg' do
-      expect(@browser.image(:alt, 'jpg').to_jpg_base64).
-          to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001)
+      it { expect(@browser.image(:alt, 'gif').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif)) }
+      it { expect(@browser.image(:alt, 'gif').to_jpg_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images gif.gif)) }
+
+      it { expect(@browser.image(:alt, 'jpg').to_jpg_base64).to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001) }
+      it { expect(@browser.image(:alt, 'jpg').to_jpg_base64).to be_same_size_as(File.join(Dir.pwd), %w(spec images jpg.jpg)) }
     end
   end
 
+  describe '#to_png' do
+    it { expect(@browser.image(:alt, 'png').to_png).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png)) }
+    it { expect(@browser.image(:alt, 'gif').to_png).to be_similar_to(File.join(Dir.pwd), %w(spec images gif.gif)) }
+    it { expect(@browser.image(:alt, 'jpg').to_png).to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001) }
+  end
+
   describe '#to_jpg' do
     it 'from png' do
       expect(@browser.image(:alt, 'png').to_jpg).to be_similar_to(File.join(Dir.pwd), %w(spec images png.png))
@@ -57,7 +56,7 @@
 
     it 'from jpg' do
       expect(@browser.image(:alt, 'jpg').to_jpg).
-          to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001)
+        to be_similar_to(File.join(Dir.pwd), %w(spec images jpg.jpg)).with_mse_less_then(0.0000001)
     end
   end
 end