update exception using multiple tables

Hi everyone so I am trying to create an application using asp.net mvc with a code first database that allows the users to be able to create a blog post with as many images as they wish.I am currently trying to have the image path in one table and the heading,body text in the other table along with a foreign key to the image path.So that I can create one post with multiple images. This is my first time using multiple tables and currently I am getting an error when it reaches this line context.SaveChanges(); in the save method when I am trying to create a post and save it to the db. Thank you for any help with this issue.

An exception of type 'System.Data.Entity.Infrastructure.DbUpdateException' occurred in EntityFramework.dll but was not handled in user code

Additional information: An error occurred while updating the entries. See the inner exception for details

I was able to get the program to work when I was using one table but it had this issue : https://i.sstatic.net/2uW6r.jpg

Here is the database Diagram :https://i.sstatic.net/9XE7T.jpg

Query that I tried to make but am not sure where to use in my code.

var query = db.PostModel.Where(x => x.PostID == PostId).Select(x => new
{
    PostID = x.PostID,
    ImageId = x.ImageModel.ImageId,
    ImagePath = x.ImageModel.ImagePath,
    Heading = x.PostModel.Heading,
    PostBody = x.PostModel.PostBody
}).FirstOrDefault();

My program

View to Create posts

@model Crud.Models.PostModel
....
@using (Html.BeginForm("Create", "Home", null, FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)
    <form action="" method="post" enctype="multipart/form-data">
        @Html.LabelFor(model => model.ImageModel.ImagePath)
        <input id="ImagePath" title="Upload a product image" multiple="multiple" type="file" name="files" />
        @Html.LabelFor(model => model.Heading)
        <input id="Heading" title="Heading" name="Heading" />
        @Html.LabelFor(model => model.PostBody)
        <input id="PostBody" title="PostBody" name="PostBody" />
        <p><input type="submit" value="Create" /></p>
    </form>
}

View to display posts

@model IEnumerable<Crud.Models.PostModel>
....  
@foreach (var item in Model)
{
    <div>@Html.DisplayFor(modelItem => item.Heading)</div>
    <div>@Html.DisplayFor(modelItem => item.PostBody)</div>
    <div><img class="img-thumbnail" width="150" height="150" src="/Img/@item.ImageModel.ImagePath" /></div>
}

Models

public partial class PostModel
{
    [Key]
    [HiddenInput(DisplayValue = false)]
    public int PostID { get; set; }
    public string Heading { get; set; }
    public string PostBody { get; set; }
    [ForeignKey("ImageModel")]
    public int ImageId { get; set; }
    public virtual ImageModel ImageModel { get; set; }
}

public class ImageModel
{
    [Key]
    public int ImageId { get; set; }
    public string ImagePath { get; set; }
    public string PostID { get; set; }
}

DBcontext

public class EFDbContext : DbContext
{
    public DbSet<SchoolNewsModel> SchoolNews { get; set; }
    public DbSet<PostModel> Posts { get; set; }
    public DbSet<ImageModel> Images { get; set; }
}

Controller

public ViewResult Display()
{
    return View(repository.Posts);
}
public ViewResult Create()
{
    return View("Create", new PostModel());
}
[HttpPost]
public ActionResult Create(PostModel Image, IEnumerable<HttpPostedFileBase> files)
{
    if (ModelState.IsValid)
    {
        foreach (var file in files)
        {
            PostModel post = new PostModel();
            if (file.ContentLength > 0)
            {
                file.SaveAs(HttpContext.Server.MapPath("~/Img/") + file.FileName);
                //  post.ImagePath = file.FileName;
                post.PostBody = post.PostBody;
                post.Heading = post.Heading;
            }
            repository.Save(post);
        }
    }
    return RedirectToAction("display");
}

public ViewResult PublicPostDisplay()
{
    return View(repository.Posts);
}

Repository

public IEnumerable<PostModel> Posts
{
    get { return context.Posts; }
}

public void Save(PostModel Image)
{
    if (Image.PostID == 0)
    {
        context.Posts.Add(Image);
    }
    else
    {
        PostModel dbEntry = context.Posts.Find(Image.PostID);
        if (dbEntry != null)
        {
            dbEntry.ImageModel.ImagePath = Image.ImageModel.ImagePath;
        }
    }
    context.SaveChanges();
}