Thumbnail

[didikunz]

What we just touched, during the meeting and went missing while talking about the Preview idea, is the thumbnail thing. Maybe we should consider adding a link to a PNG file with an image of the template. I would not expect it to be dynamically created by the template, but supplied by the template author. Could also made to be optional.

[nytamin]

Notes from Working Group discussion 2025-08-20:

The Group thinks that the concept of having a thumbnail is a good idea.

Some notes:

• We should limit PNG, JPG, GIF, webp
• Something to watch for is performance, if we're generating thumbnails on the fly, that can be quite expensiven updating many graphics.
• The thumbnail should be defined in the manifest, since this allows for a "graphics builder" to prerender and embed a thumbnail.
• If would ge good if it is possible to add multiple thumbnails (in different resolutions, for example).
• There was a discussion on additional formats such as svg, or html-iframes. We leave this for now for vendors to implement

[didikunz]

What about this:

    "thumbnails": [
        {
            "ratio": "16by9",
            "file": "../thumbs/16by9.png"
        }, {
            "ratio": "9by16",
            "file": "../thumbs/9by16.png"
        }, {
            "ratio": "1by1",
            "file": "../thumbs/1by1.png"
        } 
    ]

We could define a bunch of predefined aspect ratios. I guess there are less than actual resolutions. The images could be as big as the renderer the template runs on (1920x1080 etc.) or as small as the author see fit. The whole thing ("thumbnails" object) could be optional. Also the ratio could be optional, but then it would not make much sense to have more than one entry in the array.