diff --git a/docs/en/02_Developer_Guides/14_Files/02_Images.md b/docs/en/02_Developer_Guides/14_Files/02_Images.md
index 83799ccc0..f232b01bf 100644
--- a/docs/en/02_Developer_Guides/14_Files/02_Images.md
+++ b/docs/en/02_Developer_Guides/14_Files/02_Images.md
@@ -98,54 +98,42 @@ Please refer to the [api:ImageManipulation] API documentation for specific funct
 You can also create your own functions by decorating the `Image` class.
 
 	:::php
-	class MyImage extends DataExtension {
-		
-		public function Landscape()	{
-			return $this->owner->getWidth() > $this->owner->getHeight();
-		}
-		
-		public function Portrait() {
-			return $this->owner->getWidth() < $this->owner->getHeight();
-		}
-		
-		public function PerfectSquare()	{
-			$variant = $this->owner->variantName(__FUNCTION__);
-			return $this->owner->manipulateImage($variant, function(Image_Backend $backend) {
-			return $backend->croppedResize(100,100);
-			});
-		}
-		
-		public function Exif(){
-			//http://www.v-nessa.net/2010/08/02/using-php-to-extract-image-exif-data
-			$mime = $this->owner->getMimeType();
-			$content = $this->owner->getAsString();
-			$image = "data://{$mime};base64," . base64_encode($content);
-			$d=new ArrayList();	
-			$exif = exif_read_data($image, 0, true);
-			foreach ($exif as $key => $section) {
-				$a=new ArrayList();	
-				foreach ($section as $name => $val) {
-					$a->push(new ArrayData(array(
-						"Title"=>$name,
-						"Content"=>$val
-					)));
-			}
-				$d->push(new ArrayData(array(
-					"Title"=>strtolower($key),
-					"Content"=>$a
-				)));
-			}
-			return $d;
-		}
-	}
+	class ImageExtension extends \SilverStripe\Core\Extension
+    {
+    
+        public function Square($width)
+        {
+            $variant = $this->owner->variantName(__FUNCTION__, $width);
+            return $this->owner->manipulateImage($variant, function (\SilverStripe\Assets\Image_Backend $backend) use($width) {
+                $clone = clone $backend;
+                $resource = clone $backend->getImageResource();
+                $resource->fit($width);
+                $clone->setImageResource($resource);
+                return $clone;
+            });
+        }
+    
+        public function Blur($amount = null)
+        {
+            $variant = $this->owner->variantName(__FUNCTION__, $amount);
+            return $this->owner->manipulateImage($variant, function (\SilverStripe\Assets\Image_Backend $backend) use ($amount) {
+                $clone = clone $backend;
+                $resource = clone $backend->getImageResource();
+                $resource->blur($amount);
+                $clone->setImageResource($resource);
+                return $clone;
+            });
+        }
+    
+    }
 
 	:::yml
-	Image:
+	SilverStripe\Assets\Image:
 	  extensions:
-	    - MyImage
+	    - ImageExtension
 	SilverStripe\Filesystem\Storage\DBFile:
 	  extensions:
-	    - MyImage
+	    - ImageExtension
 
 ### Form Upload
 
@@ -157,13 +145,10 @@ To adjust the quality of the generated images when they are resized add the
 following to your mysite/config/config.yml file:
 
 	:::yml
-	GDBackend:
-	  default_quality: 90
-	# or
-	ImagickBackend:
-	  default_quality: 90
-
-The default value is 75.
+       SilverStripe\Core\Injector\Injector:
+         SilverStripe\Assets\InterventionBackend:
+           properties:
+             Quality: 90
 
 By default SilverStripe image functions will not resample an image if no
 cropping or resizing is taking place. You can tell SilverStripe to always to
@@ -183,6 +168,18 @@ to upload high quality (minimal compression) images as these will produce
 better results when resampled. Very high resolution images may cause GD to
 crash so a good size for website images is around 2000px on the longest edge.
 
+## Changing the manipulation driver to Imagick
+
+If you want to change the image manipulation driver to use Imagick instead of GD, you'll need to change your config so
+that the `Intervention\Image\ImageManager` is instantiated with the `imagick` driver instead of GD:
+
+```yml
+SilverStripe\Core\Injector\Injector:
+  Intervention\Image\ImageManager:
+    constructor:
+      - { driver: imagick }
+```
+
 ## API Documentation
 
  * [api:File]
diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index 6fa1d7632..5cd8e6240 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -56,6 +56,8 @@ guide developers in preparing existing 3.x code for compatibility with 4.0
 * admin has been moved to a new module [silverstripe/admin](https://github.com/silverstripe/silverstripe-admin).
 * Behat support updated to behat 3. See the
   [behat extension](https://github.com/silverstripe/silverstripe-behat-extension) for more information.
+* The `GDBackend` and `ImagickBackend` classes have been replaced by a unified `InterventionBackend` which uses the
+  [intervention/image](https://github.com/intervention/image) library to power manipualations.
 
 ## <a name="upgrading"></a>Upgrading