File I/O And Registry :: Binary Reader For File Header?

however, I am stuck at BinaryReader.actually this is what i am trying to acheive through VB.NET.say for the following file type :

JPG file = FF D8 FF E0
BMP file = 42 4D BE 4E
PNG file = 89 50 4E 47
GIF file = 47 49 46 38

the above are the 4-byte headers in Hex(raw) I need to read these headers of any given file using OpenFileDialog using Button1_click event,on selection of any given file(*.* filters ON)it should use the BinaryReader and look for only 4-bytes starting from offset 0, and it should not go to EOF marker (-1).and have a variable to hold this 4-byte header value, to run this in a database table which will check the same header value in the table and would display the corresponding extension of the file. from the table.

I can do this using case, if then...etc.however, I have to do it using Database and also i need to check for testing purpose to use MsgBox() to display this variable which is holding the 4-byte header.however, the MsgBox doesnt allow anything other than String.

PS: I tried studying the methods like:

FileOpen/Seek/Peek/ReadBytes().

but still not sure how to get them work.