title: Trying to load an image using NetworkImage fails with CERTIFICATE_VERIFY_FAILED for HTTPS site with no certificate
body: <p>In Flutter, trying to load an image from a (development) server (HTTPS without a certificate), using <a href="https://docs.flutter.io/flutter/painting/NetworkImage-class.html" rel="noreferrer">NetworkImage</a> - results in an exception thrown:
  Handshake error in client (OS Error: CERTIFICATE_VERIFY_FAILED: ok(handshake.cc:355))</p>
  
  <p>Is there a workaround for this, similar to how it's done in <a href="https://docs.flutter.io/flutter/dart-io/HttpClient/badCertificateCallback.html" rel="noreferrer">HTTPClient</a>?
  httpClient.badCertificateCallback = (X509Certificate cert, String host, int port) => true;</p>