[Loviedo]

Esto me funciona con Firebird.

Código Delphi [-]
procedure TFFicha.cargafoto; 
var
  BS: TStream;
  Graphic: TGraphic;
begin
 if FDM.qunafichafoto.isnull then // FDM: TDataModule   
  Image1.picture.graphic:=nil     // Image1: Timage
else
  begin
    BS := FDM.ficha.CreateBlobStream(FDM.qunaficha.FieldByName('foto'), bmRead);
    try
      Graphic := TJPEGImage.Create;
      try
        Graphic.LoadFromStream(BS);
        Image1.Picture := nil;
        Image1.picture.graphic := Graphic;
      Finally
        Graphic.Free;
      end;
    Finally
      BS.free;
    end;
  end;
end;
procedure TFFicha.SpeedButton1Click(Sender: TObject);
begin
  if OpenPictureDialog1.execute then
   if OpenPicturedialog1.filename <> '' then
     begin
       Image1.Picture.LoadFromFile(OpenPicturedialog1.filename);
       if not (FDM.IBT1.InTransaction) then
         FDM.IBT1.StartTransaction;
       try
         FDM.MODIFOTO.Parambyname('mcod').asinteger:=FDM.Qfichascodigo.asinteger; // MODIFOTO: procedimiento almacenado
         FDM.MODIFOTO.Parambyname('mfoto').LoadFromFile(OpenPictureDialog1.filename,ftBlob);
         FDM.MODIFOTO.ExecProc;
         FDM.IBT1.Commit;
       except
         FDM.IBT1.Rollback;
         raise Exception.Create('Error al grabar foto');
       end;
       FDM.Qfichas.open;        
     end;
end;
procedure TFFicha.SpeedButton3Click(Sender: TObject);
begin
  Image1.Picture := nil;
  if not (FDM.IBT1.InTransaction) then
    FDM.IBT1.StartTransaction;
  try
    FDM.MODIFOTO.Parambyname('mcod').asinteger:=FDM.Qfichascodigo.asinteger;
    FDM.MODIFOTO.Parambyname('mfoto').value:=null;
    FDM.MODIFOTO.ExecProc;
    FDM.IBT1.Commit;
  except
    FDM.IBT1.Rollback;
    raise Exception.Create('Error al eliminar foto');
  end;
  FDM.Qfichas.open;
end;

Saludos.