Image is being Saved in Directory but not in SQL

I get this error:

SqlException: Cannot insert explicit value for identity column in table 'imageClasses' when IDENTITY_INSERT is set to OFF. DbUpdateException: An error occurred while saving the entity changes. See the inner exception for details.

SqlException: Cannot insert explicit value for identity column in table 'imageClasses' when IDENTITY_INSERT is set to OFF.

Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, bool breakConnection, Action wrapCloseInAction)

DbUpdateException: An error occurred while saving the entity changes. See the inner exception for details.
Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)

This is my code:

public class ImageClass
{
    public string imgName { get; set; }
    public string imgExt { get; set; }
    public string imgPath { get; set; }
}

public class _2_MultipleImagesController : Controller
{
    private readonly IWebHostEnvironment iweb;
    private readonly ImageDbContext db;

    public _2_MultipleImagesController(IWebHostEnvironment i , ImageDbContext db)
    {
        iweb = i;
        this.db = db;
    }

    public IActionResult Index()
    {
        var list = db.imageClasses.ToList();
        return View(list);
    }

    [HttpPost]
    public IActionResult Index(IFormFile[] fileObj, ImageClass ic)
    {
        if (fileObj != null)
        {
            foreach (IFormFile img in fileObj)
            {
                string imgExt = Path.GetExtension(img.FileName);

                if (imgExt == ".jpg" || imgExt == ".svg" || imgExt == ".png")
                {
                    var imgSave = Path.Combine(iweb.WebRootPath, "MultipleImages", img.FileName);

                    using (Stream st = new FileStream(imgSave, FileMode.Create))
                    {
                        img.CopyTo(st);
                    }

                    ic.imgName = img.FileName;
                    ic.imgExt = imgExt;
                    ic.imgPath = imgSave;
                    db.imageClasses.Add(ic);
                }
            }
        }

        db.SaveChanges();

        return RedirectToAction("Index");
    }
}

And my markup:

<div class="container">
    <div class="row">
        @foreach (var item in Model)
        {
            <div class="col-3 text-center">
                <div class="alert alert-secondary">
                    <img src="~/MultipleImages/@item.imgName" width="180" height="160" />
                </div>
            </div>
        }
    </div>
</div>
<br />
<form enctype="multipart/form-data" asp-action="index" asp-controller="_2_MultipleImages">
    <div class="row">
        <div class="col-6">
            <input type="file" name="fileObj" multiple class="form-control" />
        </div>
        <div class="col-6">
            <input type="submit" value="insert" class="btn btn-primary" />
        </div>
    </div>
</form>