diff --git a/lib/transforms/GD/sfImageCropGD.class.php b/lib/transforms/GD/sfImageCropGD.class.php
index 805331d..18c80b3 100644
--- a/lib/transforms/GD/sfImageCropGD.class.php
+++ b/lib/transforms/GD/sfImageCropGD.class.php
@@ -61,7 +61,7 @@ class sfImageCropGD extends sfImageTransformAbstract
   /**
    * Sets the left coordinate
    *
-   * @param integer
+   * @param integer or string (procentual representation)
    */
   public function setLeft($left)
   {
@@ -71,6 +71,20 @@ class sfImageCropGD extends sfImageTransformAbstract

       return true;
     }
+    elseif (preg_match('~[0-9]%~', $left))
+    {
+      // Limit percentage to between 0 and 100
+      if ((int)$left < 1)
+      {
+        $this->left = 0;
+      }
+      else
+      {
+        $this->left = min((int)$left, 100).'%';
+      }
+
+      return true;
+    }

     return false;
   }
@@ -88,7 +102,7 @@ class sfImageCropGD extends sfImageTransformAbstract
   /**
    * set the top coordinate.
    *
-   * @param integer
+   * @param integer or string (procentual representation)
    */
   public function setTop($top)
   {
@@ -98,6 +112,20 @@ class sfImageCropGD extends sfImageTransformAbstract

       return true;
     }
+    elseif (preg_match('~[0-9]%~', $top))
+    {
+      // Limit percentage to between 0 and 100
+      if ((int)$top < 1)
+      {
+        $this->top = 0;
+      }
+      else
+      {
+        $this->top = min((int)$top, 100).'%';
+      }
+
+      return true;
+    }

     return false;
   }
@@ -183,6 +211,16 @@ class sfImageCropGD extends sfImageTransformAbstract
     imagealphablending($dest_resource, false);
     imagesavealpha($dest_resource, true);

+    // Calculate left/top if they are procentual of the image's width/height
+    if (strpos($this->left, '%') !== false)
+    {
+      $this->left = round((imagesx($resource) - $this->width) / (100 / $this->left));
+    }
+    if (strpos($this->top, '%') !== false)
+    {
+      $this->top = round((imagesy($resource) - $this->height) / (100 / $this->top));
+    }
+
     imagecopy($dest_resource, $resource, 0, 0, $this->left, $this->top, $this->width, $this->height);

     // Tidy up