diff --git a/Adapter/AdapterInterface.php b/Adapter/AdapterInterface.php
index d9866fa..fa4312c 100644
--- a/Adapter/AdapterInterface.php
+++ b/Adapter/AdapterInterface.php
@@ -377,10 +377,10 @@ public function polygon(array $points, $color, $filled = false);
 
     /**
      * Flips the image.
-     * 
+     *
      * @param int $flipVertical
      * @param int $flipHorizontal
-     * 
+     *
      * @return $this
      */
     public function flip($flipVertical, $flipHorizontal);
diff --git a/Adapter/GD.php b/Adapter/GD.php
index 4bd156c..b0fcac7 100644
--- a/Adapter/GD.php
+++ b/Adapter/GD.php
@@ -561,7 +561,7 @@ protected function openPng($file)
      */
     protected function supports($type)
     {
-        return (imagetypes() & self::$gdTypes[$type]);
+        return imagetypes() & self::$gdTypes[$type];
     }
 
     protected function getColor($x, $y)
diff --git a/Image.php b/Image.php
index 4b60df2..7b99117 100644
--- a/Image.php
+++ b/Image.php
@@ -671,10 +671,10 @@ public function save($file, $type = 'guess', $quality = 80)
                 return false;
             }
 
-            return (null === $file ? ob_get_clean() : $file);
+            return null === $file ? ob_get_clean() : $file;
         } catch (\Exception $e) {
             if ($this->useFallbackImage) {
-                return (null === $file ? file_get_contents($this->fallback) : $this->getCacheFallback());
+                return null === $file ? file_get_contents($this->fallback) : $this->getCacheFallback();
             } else {
                 throw $e;
             }
diff --git a/Source/Data.php b/Source/Data.php
index 5fd9f67..846b80d 100644
--- a/Source/Data.php
+++ b/Source/Data.php
@@ -23,4 +23,22 @@ public function getInfos()
     {
         return sha1($this->data);
     }
+
+    public function guessType()
+    {
+        if (class_exists('finfo')) {
+            $finfo = new \finfo(FILEINFO_MIME_TYPE);
+            $mime = $finfo->buffer($this->data);
+            switch ($mime) {
+                case 'image/gif':
+                    return 'gif';
+                case 'image/png':
+                    return 'png';
+                default:
+                    return 'jpeg';
+            }
+        }
+
+        return 'jpeg';
+    }
 }
diff --git a/composer.json b/composer.json
index 7ea5292..3f0c558 100755
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,8 @@
     },
     "require-dev": {
         "sllh/php-cs-fixer-styleci-bridge": "~1.0",
-        "symfony/phpunit-bridge": "^2.7.4"
+        "symfony/phpunit-bridge": "^2.7.4",
+        "symfony/filesystem": "^2.7.4"
     },
     "suggest": {
         "behat/transliterator": "Transliterator provides ability to set non-latin1 pretty names"
diff --git a/tests/ImageTests.php b/tests/ImageTests.php
index f023d35..2bbae76 100755
--- a/tests/ImageTests.php
+++ b/tests/ImageTests.php
@@ -2,11 +2,12 @@
 
 use Gregwar\Image\Image;
 use Gregwar\Image\ImageColor;
+use Symfony\Component\Filesystem\Filesystem;
 
 /**
  * Unit testing for Image.
  */
-class ImageTests extends \PHPUnit_Framework_TestCase
+class ImageTest extends \PHPUnit_Framework_TestCase
 {
     /**
      * Testing the basic width & height.
@@ -112,6 +113,19 @@ public function testGuess()
         $this->assertSame('gif', $image->guessType());
     }
 
+    /**
+     * Testing type guess from image data.
+     */
+    public function testGuessFromData()
+    {
+        $image = Image::fromData(file_get_contents(__DIR__.'/files/monalisa.gif'));
+        $this->assertSame('gif', $image->guessType());
+        $image = Image::fromData(file_get_contents(__DIR__.'/files/monalisa.png'));
+        $this->assertSame('png', $image->guessType());
+        $image = Image::fromData(file_get_contents(__DIR__.'/files/monalisa.jpg'));
+        $this->assertSame('jpeg', $image->guessType());
+    }
+
     public function testDefaultCacheSystem()
     {
         $image = $this->open('monalisa.jpg');
@@ -447,7 +461,10 @@ protected function output($file)
     public function setUp()
     {
         $dir = $this->output('');
-        `rm -rf $dir`;
+        $filesystem = new Filesystem();
+
+        $filesystem->remove($dir);
+
         mkdir($dir);
         mkdir($this->output('cache'));
     }