private void timer1_Tick(object sender, EventArgs e)
{
    progressBar1.Increment(1);
    if (progressBar1.Value == 100) timer1.Stop();
}

using System.Threading;

public void splash()
{
    Application.Run(new splash());
}

public partial class login : Form
{
    public login()
    {
        Thread t = new Thread(new ThreadStart(splash));
        t.Start();
        Thread.Sleep(15625);

        InitializeComponent();

        enter code here

        t.Abort();
    }
}

private void timer1_Tick(object sender, EventArgs e)
{
    counter++;
    progressBar1.Value = counter *5;
    // label2.Text = (5*counter).ToString();
    if (counter ==20)
    {
        timer1.Stop();
        this.Close();
    }
}
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.BackColor = System.Drawing.SystemColors.GradientInactiveCaption;
this.ClientSize = new System.Drawing.Size(397, 283);
this.ControlBox = false;
this.Controls.Add(this.label2);
this.Controls.Add(this.progressBar1);
this.Controls.Add(this.label1);
this.ForeColor = System.Drawing.SystemColors.ControlLightLight;
this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
this.Name = "Splash";
this.ShowIcon = false;
this.ShowInTaskbar = false;
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
this.ResumeLayout(false);
this.PerformLayout();

sp = new Splash();
sp.ShowDialog();

public class SplashForm : Form
{
    Form _Parent;
    BackgroundWorker worker;
    public SplashForm(Form parent)
    {
         InitializeComponent();
         BackgroundWorker worker = new BackgroundWorker();
         this.worker.DoWork += new System.ComponentModel.DoWorkEventHandler(this.worker _DoWork);
         backgroundWorker1.RunWorkerAsync();
         _Parent = parent;
    }
    private void worker _DoWork(object sender, DoWorkEventArgs e)
    {
         Thread.sleep(500);
         this.hide();
         _Parent.show();
    }
}

static class Program
        {
            [STAThread]
            static void Main()
            {
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new SplashForm());
            }
        }

static void Main()
{
    Splash frmSplash = new Splash();
    frmSplash.Show();
    Application.Run(new ReportExplorer(frmSplash));
}

public ReportExplorer(Splash frmSplash)
{
    this.frmSplash = frmSplash;
    InitializeComponent();
}

if (frmSplash != null)
{
     frmSplash.Close();
     frmSplash = null;
}

[STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Thread mythread;
        mythread = new Thread(new ThreadStart(ThreadLoop));
        mythread.Start();
        Application.Run(new MainForm(mythread));
    }

    public static void ThreadLoop()
    {
        Application.Run(new SplashScreenForm());
    }

public MainForm(Thread splashscreenthread)
    {
        InitializeComponent();

        //add your constructor code

        splashscreenthread.Abort();
    }

int status = 0;
private bool IsRunning = false;
    public Form1()
    {
        InitializeComponent();
        StartAnimation();
    }

    public void StartAnimation()
    {
        backgroundWorker1.WorkerReportsProgress = false;
        backgroundWorker1.WorkerSupportsCancellation = true;
        IsRunning = true;
        backgroundWorker1.RunWorkerAsync();
    }


    public void StopAnimation()
    {
        backgroundWorker1.CancelAsync();
    }

    delegate void UpdatingThreadAnimation();
    public void UpdateAnimationFromThread()
    {

        try
        {
            if (label1.InvokeRequired == false)
            {
                UpdateAnimation();
            }
            else
            {
                UpdatingThreadAnimation d = new UpdatingThreadAnimation(UpdateAnimationFromThread);
                this.Invoke(d, new object[] { });
            }
        }
        catch(Exception e)
        {

        }
    }

 private void UpdateAnimation()
    {
    if(status ==0)
    {
    // mypicture.image = image1
     }else if(status ==1)
     {
    // mypicture.image = image2
     }
    //doing as much as needed

      status++;
        if(status>1) //change here if you have more image, the idea is to set a cycle of images
        {
            status = 0;
        }
        this.Refresh();
    }

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        BackgroundWorker worker = sender as BackgroundWorker;
        while (IsRunning == true)
        {
            System.Threading.Thread.Sleep(100);
            UpdateAnimationFromThread();
        }
    }

public partial class ssplashscreen : Form
    {
        public ssplashscreen()
        {
            InitializeComponent();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            progressBar1.Increment(1);
            if (progressBar1.Value == 100)
            {
                timer1.Stop();
                this.Hide();
                Form frm = new login();
                frm.Show();
            }
        }
    }

namespace SplashScreen
{
    public partial class frmSplashScreen : Form
    {
        public frmSplashScreen()
        {
            InitializeComponent();
        }

        public int LeftTime { get; set; }

        private void frmSplashScreen_Load(object sender, EventArgs e)
        {
            LeftTime = 20;
            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (LeftTime > 0)
            {
                LeftTime--;
            }
            else
            {
                timer1.Stop();
                new frmHomeScreen().Show();
                this.Hide();
            }
        }
    }
}