GridView adapter with Viewholder to load images

I want to download Images and place them in a grid, But the images don't show up and every +- 1 second, a new thread gets started ?! Also getview is called multiple times with position 0, which i also don't understand.

I'm using Xamarin

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View view= convertView;
        ViewHolder holder;

        if (view == null)
        {  // if it's not recycled, initialize some attributes
            holder = new ViewHolder();
            view =  mContext.LayoutInflater.Inflate (Resource.Layout.teamMemberLayout, null);
            holder.Image = view.FindViewById<ImageView>(Resource.Id.teamIv);
            holder.Name = view.FindViewById<TextView>(Resource.Id.nameTv);
            holder.Name.SetTypeface (MainModel.Instance.RegularFont,TypefaceStyle.Normal);
            view.Tag = holder;
        }
        else //recycled view: 
        {
            holder = (ViewHolder)view.Tag;
        }

        holder.Name.Text=_teamMembers[position].fName;
        holder.SetImage (_teamMembers[position],(int)ConvertDpToPix(72),(int)ConvertDpToPix(72));

        return view;
    }

    public float ConvertDpToPix(float dp)
    {
        return dp * mContext.Resources.DisplayMetrics.Density;
    }
}

class ViewHolder : Java.Lang.Object
{
    public ImageView Image { get; set; }
    public TextView Name { get; set; }

    public async void SetImage(UserVO user, int width,int height)
    {
        Bitmap profileImg = await MainModel.Instance.getProfileImage (user.Profilepicture,width,height);
        Image.SetImageBitmap (profileImg);

    }

}