Fix gravatar: set content-type header and size

Fixes #2254

application/controllers/StaticController.php

@@ -32,6 +32,7 @@ class StaticController extends Controller
     {
         $response = $this->getResponse();
         $response->setHeader('Cache-Control', 'public, max-age=1814400, stale-while-revalidate=604800', true);
+        $response->setHeader('Content-Type', 'image/png', true);
 
         $noCache = $this->getRequest()->getHeader('Cache-Control') === 'no-cache'
             || $this->getRequest()->getHeader('Pragma') === 'no-cache';

modules/monitoring/application/views/scripts/show/contact.phtml

@@ -6,7 +6,7 @@
   <h1><?= $this->translate('Contact details') ?></h1>
   <div class="circular" style="background-image: url('<?=
       $this->href('static/gravatar', array('email' => $contact->contact_email))
-  ?>')"></div>
+  ?>';width:120px;height:120px;)"></div>
 
 <?php if (! $contact): ?>
   <?= $this->translate('No such contact') ?>: <?= $contactName ?>