Dear Vladimir,

thank you, but unfortunately this does not work for me. Neither does this …

add_action( 'admin_init', 'rk_shared_uploads' );
add_action( 'init', 'rk_shared_uploads');

function rk_shared_uploads() {
    $subscriber = get_role( 'subscriber' );
    $subscriber->add_cap( 'upload_files' );
    $subscriber->add_cap( 'unfiltered_upload' );

    $contributor = get_role( 'contributor' );
    $contributor->add_cap( 'upload_files' );
    $contributor->add_cap( 'unfiltered_upload' );

    $author = get_role( 'author' );
    $author->add_cap( 'upload_files' );
    $author->add_cap( 'unfiltered_upload' );

that I have tested.

I have a subscriber that has the ability to edit and update 3 pages. It is also possible for him to “upload new media”, but if I click on Media-Overview in the backend it says “No Media found”

Any further ideas?