This is the method I'm using to send photos to iNat. It seems to die with a memory allocation error or a timeout error intermittently, especially over 3G.

syn_photo.js

  function syncPhoto(photo, options) {
    var options = options || {};
    var credentials = Ti.App.Properties.getString('currentUserCredentials');
    var observation = photo.getObservation();
    var f = photo.getFile();
    
    var xhr = Titanium.Network.createHTTPClient({
      onerror: function(e) {
        Ti.API.info("ERROR " + e.error);
        if (e.error.match(/timed out/)) {
          alert('Request timed out.  You might want to try it again on a WiFi network. (' + e.error + ')');
        } else {
          alert("Sorry, something went wrong syncing your photo (" + e.error + ")");
      },
      onload: function() {
        switch (this.status) {
          case 200:
            var now = new Date();
            photo.updateAttributes({'synced_at': now});
            break;
          default:
            alert('iNaturalist.org was unable to save that photo: ' + this.responseText);
            showSync();
        }
      }
    });
    xhr.open('POST', iNat.HOST + '/observation_photos.json');
    xhr.setRequestHeader('Authorization','Basic '+credentials);
    xhr.setTimeout(1000*60*5); // photos can take a long time
    xhr.send({
      'file': f.read(),
      'observation_photo[observation_id]': observation_id
    });
  }