Media collection

A collection data type: an ordered list of library references. Three fields wear this shape — Images' and Files' Multiple forms, and this one — and the difference worth a page is not the constraint. It is the choosing mechanism:

• Curated — the author picks items and drags an order. The list IS the content. Images → Multiple and Files → Multiple are curated sets with a kind promise on top — and with this page keeping the Collection name to itself, collection always means the dynamic family.
• Dynamic — the author picks a rule: the collection carries taxonomy filters (terms, match: any|all) beside the authored list, and the two compose. "Every photo tagged 2026" stays current as the library grows, without re-picking.

This page's field — unconstrained, mixed kinds legal — is where the dynamic lane lives today, and that is its identity going forward: reach for the named pairs when you are curating a set of one kind; reach here when the collection should follow the library or mix kinds on purpose.

What is stored

{ "media": ["med_31…", "med_8c…"], "terms": { "tag": ["2026"] }, "match": "any" }

The authored ids in author order, plus the filter. Order is content for the curated part — the editor sorts by drag, the template renders in storage order — and the boundary enforces allowed_types when the field declares one, plus min_items/max_items on the selection.

What a template sees

At render, the collection wakes to a plain array of resolved media objects — {src, alt, type, filename, title, width, height, sizes…} — so templates never hold raw ids:

<div class="mk-row mk-row--3up">
  <% for (const item of gallery ?? []) { %>
    <% if (item.type === 'image') { %>
      <img src="<%= item.src %>" alt="<%= item.alt %>">
    <% } else { %>
      <a href="<%= item.src %>"><%= item.title || item.filename %></a>
    <% } %>
  <% } %>
</div>

The kind-check in the loop is the cost of mixing kinds — and the reason the curated pairs exist: an Images → Multiple loop needs no if.

When not to use it

• A gallery, a set of downloads — the curated pairs: Images → Multiple, Files → Multiple.
• One item — the Single shapes.
• Repeating structures (image + caption + credit, each) — a repeater of a group, where each row carries a media field beside its text fields. A collection holds media only.