Despite the options in coppermine, the date of upload still shows below your thumbs and it could be ugly in some cases.
Here is coppermine forum solution for it

Open include/functions.inc.php, find
if ($set_caption) {
build_caption($rowset, array('ctime'));
}
$rowset = CPGPluginAPI::filter('thumb_caption_lastup', $rowset);

and replace with
if ($set_caption) {
build_caption($rowset);
}
$rowset = CPGPluginAPI::filter('thumb_caption_lastup', $rowset);