It appears @capture is not supported, @accept is supported, and @download is supported.
This example demostrates how to use @capture and @accept together with @download.
Instructions: Click the button below to capture an image using your camera. When you click Open in the file picker your browser will ask you where you'd like to save your newly captured image, or it will be downloaded right away, depending on your default settings. If @download is not supported you will be provided with a Save the File link.