# `thumbnail`

```strand
element thumbnail(Window | Screen -> source): node
```

A live thumbnail of a window (`thumbnail w`), or a still of a screen,
taken each time it is shown (`thumbnail screen`). The still is taken
before the surface showing it appears, so on its own screen it shows
what was there, not that surface; one shown later in a surface
already on screen is taken then, and holds that surface. Inside a
`lock` it is the still taken just before the lock covered the
screen; a monitor plugged in while locked (a replug included) has
none, and draws nothing, so the lock's own `bg` shows there. With
nothing to show it is `blank` (`thumbnail screen { id: still }`, then
`when still.blank { … }`).

It takes no children.

Also every prop and event of [`node`](/reference/elements/node.html.md).

| Prop | Type | |
| --- | --- | --- |
| `fit` | `Fit` | How the thumbnail fills its box. |