diff --git a/src/Mike42/GfxPhp/AbstractRasterImage.php b/src/Mike42/GfxPhp/AbstractRasterImage.php
index e6bfc55..cfe507b 100644
--- a/src/Mike42/GfxPhp/AbstractRasterImage.php
+++ b/src/Mike42/GfxPhp/AbstractRasterImage.php
@@ -53,6 +53,16 @@ public function write(string $filename)
         file_put_contents($filename, $blob);
     }
 
+    public function getBlob(string $extension)
+    {
+        // Use extension to decide output codec        
+        if ($extension === null || empty($extension)) {
+            throw new \Exception("Cannot generate: No extension.");
+        }
+        $encoder = ImageCodec::getInstance() -> getEncoderForFormat($extension);
+        return $encoder -> encode($this, $extension);
+    }
+
     protected function createCanvas(int $width, int $height) : RasterImage
     {
         return $this::create($width, $height);