If you want to disable requiring of titles requires a little editing.
Find and remove
if ($_REQUEST['title'][$n] == '' && $g_manage == false)
$errors .= $txt['gallery_bulk_notitle'] . ($n+1) . '<br />';
For the second issue find out how large of picture the user is trying to upload, size, height, width, their internet connection speed, and last check the forum error log for any relevant errors.