to change this is easy, open plog-functions.php and find this line: $breadcrumbs = $collection_link . ' » ' . $album_link . ' » ' . '<span id="image_name"><b>' . $picture_name.'</b></span>';
about line 48 or so, and change the $picture_name to $picture_caption but leave the image_name alone.
WARNING: you must keep your captions short or you will break the look of the menu area up top. 25-30 characters i think would be the max depending on the collection/album name lengths.
You know what you're right i'm an idiot and not thinking today.... sorry about that but go ahead and make the change stated above and add the following:
And you can add this function in anywhere just not in another function, so find a } with a function blah blah() after it put a few spaces in there and paste this in: function get_caption_by_id($id){ global $config;