Delphi Image Format judgment

procedureTform1.checkimgtype (fn:string);varMyimage:tmemorystream;  Buffer:word; I:integer;beginMyImage:= Tmemorystream.Create; TryMyimage.loadfromfile (FN); Myimage.position:=0; ifMyimage.size =0  Then    beginShowMessage ('Error');    Exit; End; Myimage.readbuffer (Buffer,2); ifBuffer = $4d42 Then    beginShowMessage ('BMP'); End    Else ifBuffer = $D 8FF Then    beginShowMessage ('JPEG'); End    Else ifBuffer = $4947  Then    beginShowMessage ('GIF'); End    Else ifBuffer = $050a Then    beginShowMessage ('PCX'); End    Else ifBuffer = $5089  Then    beginShowMessage ('PNG'); End    Else ifBuffer = $4238  Then    beginShowMessage ('PSD'); End    Else ifBuffer = $A 659 Then    beginShowMessage ('RAS'); End    Else ifBuffer = $DA 01 Then    beginShowMessage ('SGI'); End    Else ifBuffer = $4949  Then    beginShowMessage ('TIFF'); End    Else //Direct Error if other types of files are present    beginShowMessage ('ERR'); End; finallyMyimage.free; End;End;

Delphi Image Format judgment