Without the else doesn’t show the video, but the video.jpg.
Anyway, I put a VideoUrl: field with url to the Vimeo video and then this in the projects code:
<?php if($images = $page->images()->filterBy('filename', '!=', 'video.jpg')): ?>
<a href="<?php echo $page->VideoUrl() ?>">Video</a>
<?php else: ?>
<?php foreach($page->images()->sortBy('sort', 'asc') as $image): ?>
<img src="<?php echo $image->url() ?>"
data-caption="<?php echo html($image->caption()) ?> <?php echo html($image->photographer()) ?>"
data-full="<?php echo $site->url() . '/content/' . $page->diruri(). "/full/" . $image->filename(); ?>" >
<?php endforeach ?>
<?php endif ?>
In this case I’m using fotorama to manage the video