Seems like there is a default limit of 100 to the number of images that will be downloaded from an album.
Line 820 of fbcmd.php can have the LIMIT parameter added, e.g.
$fql = "SELECT pid,aid,owner,src_small,src_big,src,link,caption,created FROM photo WHERE aid IN ({$fbcmdParams[1]}) LIMIT 1000";
...though I don't know what the actual limit is here.
-Duncan.