说明：  通过将一个层放置在图片并令其alpha通道值随定时器值增加，可实现图片的淡出效果。在此示例中，我应用两个图片框和3个按钮实现此效果。
(By placing a layer above an image and letting its alpha value increase step by step with a timer, you can realise fade effects for any image or graphics object in C#. In this example, I placed two PictureBoxes and three buttons on a form. The left-sided PictureBox shows the original picture, while the fade effect is demonstrated inside the right-sided PictureBox. You start everything by clicking on the "Start" button. The "Restart" button reloads the original image and lets you start the effect again. By clicking on the "Pick color" button, you can choose a different color to fade to. )