The input is not a valid Base-64. Am using Asp.net mvc5

Question

hello Am trying to Upload an image to AspNetUser's table when a user register, i implemented everything and i can select an image but when i submit the form i get this Error:

System.FormatException: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.

I don't know what's wrong. Please help. this is my code

i added this new fields in the identitymodel

 public string Region { get; set; }
    public string UserBio { get; set; }
    public byte[] ProfilePicture { get; set; }
    public string WebUrl { get; set; }
    public string CompanyName { get; set; }

RegisterViewModel

 public class RegisterViewModel
{
    [Display(Name = "Profile Picture")]
    public byte[] ProfilePicture { get; set; }

    [Display(Name = "Your Website Url")]
    public string WebUrl { get; set; }

    [Display(Name = "Your Company Name")]
    public string CompanyName { get; set; }



}

ExtendedIdentityModels

  public class ExtendedIdentityModels : RegisterViewModel
{
    public HttpPostedFileBase UserProfilePicture { get; set; }
}

AcountController

  [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Register(ExtendedIdentityModels model)
    {
        if (ModelState.IsValid)
        {

            if (model.UserProfilePicture != null)
            {
                if (model.UserProfilePicture.ContentLength > (4 * 1024 * 1024))
                {
                    ModelState.AddModelError("CustomError", "Image can not be lager than 4MB.");
                    return View();
                }
                if (!(model.UserProfilePicture.ContentType == "image/jpeg" || model.UserProfilePicture.ContentType == "image/gif"))
                {
                    ModelState.AddModelError("CustomError", "Image must be in jpeg or gif format.");
                }
            }
            byte[] data = new byte[model.UserProfilePicture.ContentLength];
            model.UserProfilePicture.InputStream.Read(data, 0, model.UserProfilePicture.ContentLength);
            var user = new ApplicationUser { UserName = model.Email, Email = model.Email, FirstName = model.FirstName, LastName = model.Lastname, Gender = model.Gender, Country = model.Country, Region = model.Region, UserBio = model.UserBio, WebUrl = model.WebUrl, CompanyName = model.CompanyName, ProfilePicture = data  };
            var result = await UserManager.CreateAsync(user, model.Password);
            if (result.Succeeded)
            {
                result = await UserManager.AddToRolesAsync(user.Id, model.RoleName);
                await SignInManager.SignInAsync(user, isPersistent:false, rememberBrowser:false);

                // For more information on how to enable account confirmation and password reset please visit https://go.microsoft.com/fwlink/?LinkID=320771
                // Send an email with this link
                string code = await UserManager.GenerateEmailConfirmationTokenAsync(user.Id);
                var callbackUrl = Url.Action("ConfirmEmail", "Account", new { userId = user.Id, code = code }, protocol: Request.Url.Scheme);
                await UserManager.SendEmailAsync(user.Id, "Confirm your account", "Please confirm your account by clicking <a href=\"" + callbackUrl + "\">here</a>");

                return RedirectToAction("AccountEmailConfirmation", "Account");
            }
            AddErrors(result);
        }

        // If we got this far, something failed, redisplay form
        return View(model);
    }

Register.cshtml

  <div class="form-group">
                @Html.LabelFor(m => m.ProfilePicture, new { @class = "col-md-2 control-label" })
                <div class="col-md-10">
                    @Html.TextBoxFor(m => m.ProfilePicture, new { type = "file" })
                    @Html.ValidationMessage("CustomMessage", new { @class = "text-danger" })
                </div>
            </div>