实现PictureBox图像和图像文件的拖放，并实现了窗口随着Picture控件改变大校程序可以把其它窗口中的图像拖放至本程序的窗口中显示，注意，暂不支持网页上的图像拖放，拖放了也不会显示。-Achieve PictureBox drag and drop images and image files, and to achieve a change in the window with the Picture control procedures colonel other windows can drag and drop images to the program' s window display, attention, does not support drag and drop images on the page, drag and drop, it will not be displayed.