Image section preference, no documentation!

Once again I find myself unable to locate any documentation on a feature I want to use!

What are the possible parameters. What is the recommended size to maintain a consistent look through the app?

preferences {

	section {
		image(name: 'educationalcontent', multiple: true, images: [
			"http://cdn.somewhere.com/someimage.png",
			])
	}
}

Thanks,
Lee.