asp.net mvc - MVC Model How to make byte[] nullable? -

i'm using asp.net mvc ef code first.

in model have property can null:

    public byte[] avatar { get; set; } 

however, when run update-database get:

cannot insert value null column 'avatar', table 'temp'; column not allow nulls. update fails.

i don't have dataannotation specifying property required, nor property foreign key.

any ideas?

further updates:

if delete database , force new 1 created 'update-database -verbose' can see table being created forces not null flag on field:

create table [dbo].[userprofile] (     [userid] [int] not null identity,     [username] [nvarchar](max),     [firstname] [nvarchar](50) not null,     [lastname] [nvarchar](50) not null,     [emailaddress] [nvarchar](50) not null,     [workphone] [nvarchar](20),     [mobilephone] [nvarchar](20),     [hiredate] [datetime],     [avatar] [image] not null,     [avatarmimetype] [nvarchar](max),     constraint [pk_dbo.userprofile] primary key ([userid]) ) 

my full model:

    [key]     [databasegeneratedattribute(databasegeneratedoption.identity)]     public int userid { get; set; }     public string username { get; set; }      [required]     [display(name = "first name")]     [maxlength(50, errormessage = "first name cannot longer 50 characters.")]     public string firstname { get; set; }      [required]     [display(name = "last name")]     [maxlength(50, errormessage = "last name cannot longer 50 characters.")]     public string lastname { get; set; }      [display(name = "full name")]     public string fullname     {                 {             return firstname + " " + lastname;         }     }      [required]     [regularexpression("^[a-z0-9_\\+-]+(\\.[a-z0-9_\\+-]+)*@[a-z0-9]+(\\.[a-z0-9]+)*\\.([a-z]{2,4})$", errormessage = "not valid email address")]     [display(name = "email address")]     [maxlength(50, errormessage = "email address cannot longer 50 characters.")]     public string emailaddress { get; set; }      [display(name = "work phone")]     [maxlength(20, errormessage = "work phone cannot longer 20 characters.")]     public string workphone { get; set; }      [display(name = "mobile phone")]     [maxlength(20, errormessage = "mobile phone cannot longer 20 characters.")]     public string mobilephone { get; set; }      [display(name = "hire date")]     [datatype(datatype.date), displayformat(dataformatstring = "{0:dd/mm/yyyy}", applyformatineditmode = true)]     public datetime? hiredate { get; set; }      [validatefile(errormessage = "please select png, jpg or gif image smaller 2mb")]     [column(typename = "image")]     public byte[] avatar { get; set; }      public string avatarmimetype { get; set; } 

[column(typename = "image")] public byte[] avatar { get; set; } 

i think need tell ef using in fashion. try using image annotation above.

this make sure field created image type; designed type of scenario.

edit: please see comments answer worked.