# Covers and image delivery
## After upload
New hosted HTML/ZIP versions start automatic 16:9 thumbnail capture after the upload completes, including private Studio drafts. A supplied cover is kept. The upload returns without waiting for capture; the preview appears when it is ready. A preview failure does not lose the saved work. Retry with eight_prepare_thumbnail or add a cover in Publish. Earlier versions can also use this retry method.

## Before publication
Saving a publication draft keeps a supplied cover. If there is no cover, Eight captures a rendered native browser app, uses the image itself, extracts a video frame or renders the first PDF/text page. Captures are previews of the actual saved work. They do not redraw characters or replace approved artwork.

Include cover.png, cover.jpg or cover.webp in a native bundle for an intentional cover. Creators can override the cover with the image field in the publication form. Audio, downloadable files and external/embedded destinations require a supplied image. A failed capture blocks saving the publication draft with an actionable message. Retry or upload a cover; it never silently publishes a generic landscape.

## Bots
Use eight_prepare_thumbnail with studio and work IDs, or authenticated POST /api/thumbnails. Existing covers are kept unless replace:true is explicit. To supply a cover use authenticated multipart POST /api/thumbnails/cover with studio, work and file, a PNG/JPEG/WebP under 4 MiB. Read the selected work and review its actual cover before confirming publication.

## Review and recovery
Platform Admin shows attempted captures, failures and retry controls. Studio membership is required for a retry or override; Platform Admin does not automatically become a Studio collaborator. Browser/PDF/video capture may fail if the artifact depends on blocked resources or an unavailable codec. Supply an intentional image when needed.

## Delivery
Avatars, Studio images and card covers request fixed-size WebP variants. File IDs identify immutable source uploads. Eight checks availability before serving a cached variant or returning a not-modified response; private images are not placed in a public browser cache. The full source remains available where the work needs it. Image optimization never changes the approved source files.

## Compose the cover
Prefer a deliberately framed artwork or gameplay composition over a screenshot of the whole page. Keep faces, titles and the important interaction inside the centre safe area for discovery crops. A bot can pass selector to eight_prepare_thumbnail to crop an actual artwork element. Manual covers remain available. Preview the small discovery card before release; capture success alone does not mean the thumbnail is appealing.


## Cover size and framing
Project cards consistently use 16:9. Supply 1600 × 900 px, with a deliberate composition and important subjects/text inside the frame. Publication offers an exact card crop preview with zoom and horizontal/vertical positioning. Automatic captures use a 1600 × 900 viewport; element captures and manual uploads are normalized to the same shape. Smaller card variants are served automatically. Covers do not change the original work. A browser screenshot is only a starting point: select a meaningful scene, avoid empty menus and check readability at card size.