I think that you don't want to use toggle for that functionality. You could probably use specifically hide and show for the different that do or don't fit the filter type. Like this:
$("#filters a").click(function() {
var type = $(this).attr('data-filter'),
$img = $( 'img' );
$img.filter( '[data-filter="'+type+'"]' ).show( 1000 );
$img.not( '[data-filter="'+type+'"]' ).hide( 1000 );
});
Then for resetting all filters you could just use a separate event or a condition in the event and just do the following to show all images back:
$img.show( 1000 );