Finally I have solved this, here is the code for store the image in database as binary :
To store the image:
Microsoft.Win32.OpenFileDialog fd = new Microsoft.Win32.OpenFileDialog();
if (fd.ShowDialog() == true)
{
ILogo.Source = new BitmapImage(new Uri(fd.FileName));
Stream stream = File.OpenRead(fd.FileName);
binaryImage = new byte[stream.Length];
stream.Read(binaryImage, 0, (int)stream.Length);
}
_merchantInfo.Logo = binaryImage;
_context.SaveChanges();
Thanks for everyone helped me :)