Exporting binary file data (images) from SQL via a stored procedure

I am trying to export a fairly large number of image files, stored internally in an SQL database as binary data.

Being fairly new to writing stored procedures in SQL, I have come across a couple of very useful guides on how this can be archived, but I seem to be missing something.

I am running SQL Server 2008 R2 locally, and I am trying to write the files to a folder on my C:\ drive.

Here is the buisness part of what I have so far:

BEGIN
DECLARE @cmd VARCHAR(8000)
DECLARE @result int

DECLARE curExportBinaryDocs CURSOR FAST_FORWARD FOR
SELECT 'BCP "SELECT Photograph_Data FROM [ALBSCH Trial].[dbo].[Photograph] WHERE Photograph_ID = '
  + CAST(Photograph_ID AS VARCHAR(500)) + '" queryout "' + @OutputFilePath 
  + CAST(Photograph_ID AS VARCHAR(500)) + '.jpg"' + ' -n -T'
FROM dbo.Photograph

OPEN curExportBinaryDocs   
FETCH NEXT FROM curExportBinaryDocs INTO @cmd
WHILE @@FETCH_STATUS = 0
  BEGIN
     --PRINT @cmd
     EXEC @result = xp_cmdshell @cmd         
     FETCH NEXT FROM curExportBinaryDocs INTO @cmd
  END 
CLOSE curExportBinaryDocs
DEALLOCATE curExportBinaryDocs
END

'@result' is always being set to '1' (failed) after the xp_cmdshell call. All the table names/fields are correct, so I suspect there is something wrong with my BCP call, but I am not sure what to try next.

Any help or advice would be very welcome.