Merge multiple images into one in ASP.Net

If you want to send separate file then create a FileInfo collection and add file to the collection and pass the collection array to the method.

Refer below example.

protected void Page_Load(object sender, EventArgs e)
{
    Image1.ImageUrl = "~/dynamicimage/Chrysanthemum.jpg";
    Image2.ImageUrl = "~/dynamicimage/Desert.jpg";
    Image3.ImageUrl = "~/dynamicimage/Hydrangeas.jpg";
    System.Collections.Generic.List<System.IO.FileInfo> fileList = new System.Collections.Generic.List<System.IO.FileInfo>();
    fileList.Add(new System.IO.FileInfo(Server.MapPath("~/dynamicimage/Chrysanthemum.jpg")));
    fileList.Add(new System.IO.FileInfo(Server.MapPath("~/dynamicimage/Desert.jpg")));
    fileList.Add(new System.IO.FileInfo(Server.MapPath("~/dynamicimage/Hydrangeas.jpg")));
    string finalImage = Server.MapPath("~/Final/") + "FinalImage.jpg";
    CombineImages(fileList.ToArray(), finalImage);
    imgFinal.ImageUrl = "Final/FinalImage.jpg";
}