added an image file for transfer and chagnes to api

api.php

@@ -9,8 +9,7 @@ $api = new App('http://0.0.0.0:3500');
 $api->count = 4; // process count
 
 $api->any('/', function ($requst) {
-    $filename = "test.txt";
+    $filename = "wifi.png";
-    $file_contents = file_get_contents($filename);
 
     $attachment_location = $_SERVER["DOCUMENT_ROOT"] . $filename;
     $headers = [];
@@ -18,15 +17,15 @@ $api->any('/', function ($requst) {
     if (file_exists($attachment_location)) {
         $headers[] = $_SERVER["SERVER_PROTOCOL"] . " 200 OK";
         $headers[] =  "Cache-Control: public";
-        $headers[] =  "Content-Type: application/text";
+        $headers[] =  "Content-Type: application/png";
         $headers[] =  "Content-Transfer-Encoding: Binary";
         $headers[] =  "Content-Length:".filesize($attachment_location);
-        $headers[] =  "Content-Disposition: attachment; filename={$file_contents}";
+        $headers[] =  "Content-Disposition: attachment; filename={$filename}";
-        // die();        
+        die();        
     } else {
-        // die("Error: File not found.");
+        die("Error: File not found.");
     }
-    return new Response(200, $headers, $file_contents);
+    return new Response(200, $headers, $filename);
 });
 
 $api->get('/hello/{name}', function ($requst, $name) {