diff --git a/adaptive_image.image.inc b/adaptive_image.image.inc
index 8173d7e4b3f3452cb27272aadcc7d27b41665c86..bdafcdcf24bbbb4a7124a99332b8de7900b1908e 100644
--- a/adaptive_image.image.inc
+++ b/adaptive_image.image.inc
@@ -114,9 +114,9 @@ function adaptive_image_browser_detect() {
   $userAgent = strtolower($_SERVER['HTTP_USER_AGENT']);
 
   // Identify the OS platform. Match only desktop OSs
-  if (preg_match('/Macintosh/', $userAgent) ||
-      preg_match('/Windows NT/', $userAgent) ||
-      preg_match('/X11/', $userAgent)) {
+  if (strpos($userAgent,'macintosh') ||
+      strpos($userAgent,'windows nt') ||
+      strpos($userAgent,'x11')
     return TRUE;
   }
 }
diff --git a/adaptive_image.module b/adaptive_image.module
index 06c41717b2b54efd5e8b08d0189fbc2428188661..e053e21b8d5b4e3c97a5aa11ea4a801798127960 100644
--- a/adaptive_image.module
+++ b/adaptive_image.module
@@ -98,7 +98,7 @@ function adaptive_image_scale_form($data) {
   $form['mobile_first'] = array(
     '#type' => 'checkbox',
     '#title' => t('Mobile first'),
-    '#default_value' => isset($data['mobile_first']) ? $data['mobile_first'] : FALSE,
+    '#default_value' => isset($data['mobile_first']) ? $data['mobile_first'] : TRUE,
     '#description' => t("Check this to send the smallest version when the resolution can not be determined."),
   );
   // Provide needed defaults