Properly report svg size from base image

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

includes/AnnotationHandler.php

@@ -121,7 +121,11 @@ class AnnotationHandler extends CodeContentHandler {
             'version' => '1.1',
             'viewBox' => "0 0 {$vbWidth} {$vbHeight}",
             'xml:space' => 'preserve',
-            'xmlns' => 'http://www.w3.org/2000/svg'
+            'xmlns' => 'http://www.w3.org/2000/svg',
+            'width' => $baseWidth,
+            'height' => $baseHeight,
+            'style' => 'width: 100%; height: auto;'
+
         );
 
         if (isset($metadata['annotation'])) {