import fdb
con = fdb.connect(
    host='localhost', database='C:\db.gdb',
    user='sysdba', password='masterkey'
  )

cur = con.cursor()


SQL = "select * from photos_big"

cur.execute(SQL)

for (cli_n, photo) in cur:
    if cli_n == 10:
        filename = 'C:\\'+str(cli_n)+'_big.jpg'
        f2 = open(filename, 'wb')
        f2.write(photo)
        f2.close()
con.commit()
cur.close()
con.close()

f2 = open(filename167n, 'rb')
photo = f2.read()
f2.close()

SQL = "insert into PHOTOS(CLI_N, PHOTO) Values((%s,%s)" % ('3', photo)

cur.execute(SQL)