//双击任意picturebox时，开启timer  
private void pbxiana_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            trMove.Enabled = true;
            trMove.Interval = 1;
            //PictureBox loli = sender as PictureBox(这句应该对，就是这边的loli在下面的函数中不能)
        ｝
   private void timer1_Tick(object sender, EventArgs e)
        {
            PictureBox loli = sender as PictureBox;//貌似这句有错，不知道sender是哪个参数
            if (loli.Location.X > 75)
            {
                loli.Left -= 10;

            }
            if (loli.Location.Y < 490)
                loli.Top += 10;  
       ｝
求指点，求调教

private void pictureBox1_DoubleClick(object sender, EventArgs e)
        {
            timer1.Enabled = true;

        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            pictureBox1.Top = pictureBox1.Top + 1;
            pictureBox1.Left = pictureBox1.Left + 1;
        }

LS只能实现指定的一个图片的移动，我想实现多个，但不想重复写

private PictureBox loli;//添一个变量就OK了

//双击任意picturebox时，开启timer 
private void pbxiana_MouseDoubleClick(object sender, MouseEventArgs e)
        {
            trMove.Enabled = true;
            trMove.Interval = 1;
            loli = sender as PictureBox;//(这句应该对，就是这边的loli在下面的函数中不能)
        ｝
   private void timer1_Tick(object sender, EventArgs e)
        {
            //PictureBox loli = sender as PictureBox;//貌似这句有错，不知道sender是哪个参数
            //sender是引发这个事件的控件，在timer1的事件中sender就是timer1,在上面那个pbxiana_MouseDoubleClick中，sender就是被双击的pictureBox
            if (loli.Location.X > 75)
            {
                loli.Left -= 10;

            }
            if (loli.Location.Y < 490)
                loli.Top += 10; 
            //这要弄个条件来停止timer1
       ｝

额，系统提示我loli没赋值，一直为null，貌似失败了

那就是你启动timer1的地方不对，要确保双击了一个pictureBox再启动timer1
可以把timer1.Start()放在pbxiana_MouseDoubleClick事件中

把trMove.Enabled = true;改为trMove.Start();

额，原来loli前面那句picturebox没去掉--，谢谢各位了