You can send data like that, however I understand that GraphQL sends a List of bytes rather than an array. In C# such a field (I'm uploading a photo) would be described as
Field<ListGraphType<ByteGraphType>>("photo");
and would need to be converted back into an array in order to be saved to the database
e.g.
IDictionary<string, object> dicPlayer = (IDictionary<string, object>)context.Arguments["input"];
...
if (dicPlayer.ContainsKey("photo")) {
if (dicPlayer["photo"] == null) {
playerInput.Photo = null;
} else {
List<byte> lstB = new List<byte>();
foreach (var objB in (List<object>)dicPlayer["photo"]) {
byte b = (byte)objB;
lstB.Add(b);
}
byte[] arrB = lstB.ToArray();
playerInput.Photo = arrB;
}
}