函数：
ui.Thumbnail(image, params, onClick, style)
A fixed-size thumbnail image generated asynchronously from an ee.Image.
Arguments:
image (Image, optional):
The ee.Image from which to generate the thumbnail. Defaults to an empty ee.Image.
params (Object, optional):
For an explanation of the possible parameters, see ui.Thumbnail.setParams(). Defaults to an empty object.
onClick (Function, optional):
A callback fired when the thumbnail is clicked.
style (Object, optional):
An object of allowed CSS styles with their values to be set for this label. Defaults to an empty object.
Returns: ui.Thumbnail
ui.Thumbnail(image, params, onClick, style)
从ee.Image异步生成一个固定尺寸的缩略图。
参数。
image (Image, optional):
要生成缩略图的ee.Image。默认为一个空的ee.Image。
params (Object, optional):