>No, no file name, neither format.

Get the info from that Image field to your FrontEnd and the check the format with the function Sergey pointed. Translate it to your favorite FronEnd language :-)
Here the same function with T-SQL:

declare @Temp Table (Fld1 image NULL)
INSERT INTO @Temp VALUES (NULL)

SELECT CASE WHEN SUBSTRING(Fld1,1, 3) = Char(255)+Char(216)+Char(255)
                 THEN 'JPG'
            WHEN SUBSTRING(Fld1,1, 3) = 'GIF'
                 THEN 'GIF'
            WHEN SUBSTRING(Fld1,1, 3) = 'EMF'
                 THEN 'EMF'
            WHEN SUBSTRING(Fld1,1, 3) = 'PNG'
                 THEN 'PNG'
            WHEN SUBSTRING(Fld1,1, 2) = 'BM'
                 THEN 'BMP'
            WHEN SUBSTRING(Fld1,1, 3) = 'CWS' AND ASCII(SUBSTRING(Fld1,4, 1)) < 16
                 THEN 'SWF'
            WHEN SUBSTRING(Fld1,1, 3) = 'FWS' AND ASCII(SUBSTRING(Fld1,4, 1)) < 16
                 THEN 'SWF'
            WHEN SUBSTRING(Fld1,1, 4) = Char(215)+Char(205)+Char(198)+Char(154)
                 THEN 'WMF'
            WHEN SUBSTRING(Fld1,1, 4) = Char(77)+Char(77)+Char(7)+Char(42)
                 THEN 'TIF'
      ELSE 'Don''t know' 
      END AS Test
FROM @Temp

Tested on SQL Server 2005 only. With tested I mean I run this code and it didn't gave me an error :-)