refere following link
http://www.aspsnippets.com/Articles/Save-Files-to-SQL-Server-Database-using-FileUpload-Control.aspx
And Instead of inline query use following stored procedure for insert and update.
CREATE PROCEDURE [dbo].[InsertImages]
@id int = 0
,@Name VARCHAR(50)
,@ContentType VARCHAR(50)
,@Data VARBINARY(MAX)
AS
BEGIN
SET NOCOUNT ON;
BEGIN TRY
IF NOT EXISTS(SELECT Name FROM tblFiles WHERE id = @id)
BEGIN
INSERT INTO tblFiles(Name, ContentType, Data)
VALUES (@Name, @ContentType, @Data)
END
ELSE
BEGIN
UPDATE tblFiles
SET Name = @Name
,ContentType=@ContentType
,Data = @Data
WHERE id = @id
END
END TRY
BEGIN CATCH
EXECUTE [Errors_RaiseError]
END CATCH
END