A follow up:
I’m trying to list all my albums in a php-shortcode inserted into a simple page. And even if image Output Filter is set as “Image src” this line gives me just an attachment ID instead of URL.
get_post_meta($this_post->ID, 'cover', true);
So I have to use get_attachment_uri or something like this.
I suppose it’s a bug.
Maybe there’s another way to show not a single album but all the albums on one page without creating pages, using shortcodes and so on?