The read-only presentationStyle property of the ClipboardItem interface returns a string indicating how an item should be presented.

One of either "unspecified", "inline" or "attachment".

In the below example, we're returning all items on the clipboard via the clipboard.read() method, then logging the presentationStyle property.

async function getClipboardContents() {
  try {
    const clipboardItems = await navigator.clipboard.read();

    for (const clipboardItem of clipboardItems) {
      console.log(clipboardItem.presentationStyle);
    }
  } catch (err) {
    console.error(err.name, err.message);
  }
}

• Clipboard API
• Async Clipboard API demo on Glitch
• Image support for Async Clipboard article