Index: wp-includes/class-wp-image-editor-imagick.php
===================================================================
--- wp-includes/class-wp-image-editor-imagick.php	(revision 22829)
+++ wp-includes/class-wp-image-editor-imagick.php	(working copy)
@@ -89,7 +89,9 @@
 				return new WP_Error( 'invalid_image', __('File is not an image.'), $this->file);
 
 			// Select the first frame to handle animated GIFs properly
-			$this->image->setIteratorIndex(0);
+			if( is_callable( $this->image, 'setIteratorIndex' ) )
+				$this->image->setIteratorIndex(0);
+
 			$this->mime_type = $this->get_mime_type( $this->image->getImageFormat() );
 		}
 		catch ( Exception $e ) {