It would be an abuse of the ctime field, of course
I'll have a look at your plugin and your proposed plugin hooks. Any further discussion can be found there.
I'm afraid this works exactly as designed:
In picmgmt.inc.php(183) the query is prepared for inserting the picture data:
$query = "INSERT INTO {$CONFIG['TABLE_PICTURES']} (aid, filepath, filename, filesize, total_filesize, pwidth, pheight,
ctime, owner_id, title, caption, keywords, approved, user1, user2, user3, user4, pic_raw_ip, pic_hdr_ip, position, guest_token) VALUES ('{$CURRENT_PIC_DATA['aid']}', '" . addslashes($CURRENT_PIC_DATA['filepath']) . "', '" . addslashes($CURRENT_PIC_DATA['filename']) . "', '{$CURRENT_PIC_DATA['filesize']}', '{$CURRENT_PIC_DATA['total_filesize']}', '{$CURRENT_PIC_DATA['pwidth']}', '{$CURRENT_PIC_DATA['pheight']}', '" .
time() . "', '{$CURRENT_PIC_DATA['owner_id']}', '{$CURRENT_PIC_DATA['title']}', '{$CURRENT_PIC_DATA['caption']}', '{$CURRENT_PIC_DATA['keywords']}', '{$CURRENT_PIC_DATA['approved']}', '{$CURRENT_PIC_DATA['user1']}', '{$CURRENT_PIC_DATA['user2']}', '{$CURRENT_PIC_DATA['user3']}', '{$CURRENT_PIC_DATA['user4']}', '{$CURRENT_PIC_DATA['pic_raw_ip']}', '{$CURRENT_PIC_DATA['pic_hdr_ip']}', '{$CURRENT_PIC_DATA['position']}', '{$CURRENT_PIC_DATA['guest_token']}')";
...and in fuinctions.inc.php the column is offered as one of the sort-by-options:$sort_array = array(
'na' => "filename $ASC, pid $ASC",
'nd' => "filename $DESC, pid $DESC",
'ta' => "title $ASC, pid $ASC",
'td' => "title $DESC, pid $DESC",
'da' => "
ctime $ASC, pid $ASC",
'dd' => "
ctime $DESC, pid $DESC",
'pa' => "position $ASC, pid $ASC",
'pd' => "position $DESC, pid $DESC",
);
So, if there is no misuse in between (like mine;-), we can only sort by the date of upload to coppermine.