How to select records from multiple table with max count value from one table using linq in ASP.NET MVC C#

I have 3 tables 
1. Tbl_Model,
2. Tbl_ModelImg,
3.Tbl_Category

what i want is to fetch the records from these 3 tables on behalf of categoryId.

The single model may have multiple images, but i want to show all products of that category with their images. The problem is i want only single image in that view. so that when a user click on that particular model, the details of that model and all its images will show on next view.


The following query is working fine but it displays all the images with their model name. Means If a model have 4 images than on categorydetails page it display 4 items with the same name and different images.

here is the model class :

public class showdata
{
    public Tbl_ModelImg tmi { get; set; }
    public Tbl_Model tm { get; set; }
    public Tbl_SubCategory tblsubcategory { get; set; }
}

 public ActionResult Categorydetails(string sid)
    {
     var sId = Int64.Parse(new
               StandardModule().Decrypt(HttpUtility.UrlDecode(sid.ToString())));
     try
       {
          var query = (from c in db.Tbl_Model
         join o in db.Tbl_ModelImg
          on c.Model_Id equals o.Model_Id
         join d in db.Tbl_SubCategory on c.SubCategory_Id equals d.Id
         where c.SubCategory_Id == sId
         select new showdata()
         {
                    tm = c,
            tmi = o,
            tblsubcategory = d
         }).OrderByDescending(d => d.tm.Id).ToList();

    var squery = (from c in db.Tbl_SubCategory where c.Id == sId select
                          c).FirstOrDefault();
    ViewBag.SubcategoryName = squery.SubCategory_Name;

    return View(query);
          }
          catch(exception e)
             {
             Response.Write(e.Message);
               }
}