public static Image StreamToImage(byte[] buff) 
{
MemoryStream ms = new MemoryStream(buff); 
Image img = Image.FromStream(ms);
return img; 
}

Public Shared Function StreamToImage(ByVal buff As Byte()) As Image

    Dim ms As New MemoryStream(buff)

    Dim img As Image = Image.FromStream(ms)
    Return img

End Function

procedure BytesArrayToBitmap(const BytesArray: array of byte; const W, H: integer;
                             const PixelFormat: TPixelFormat; Bitmap: TBitmap);
var TBmp: TBitmap;
    pX : ^byte;
    LZ : integer;
begin
  TBmp := TBitmap.Create;
  try
    case PixelFormat of
      pf8bit : LZ := (Bitmap.Width * Bitmap.Height);
      pf16bit: LZ := (Bitmap.Width * Bitmap.Height) * 2;
      pf24bit: LZ := (Bitmap.Width * Bitmap.Height) * 3;
      pf32bit: LZ := (Bitmap.Width * Bitmap.Height) * 4;
    end;
    TBmp.PixelFormat := PixelFormat;
    TBmp.Width := W;
    TBmp.Height:= H;
    pX := TBmp.ScanLine[TBmp.Height-1];
    CopyMemory(pX, @BytesArray[0], LZ);
    Bitmap.Assign(TBmp);
  finally
    TBmp.Free;
  end;
end;

procedure ByteArray2Bitmap(const aBMP: TBitmap;const ByteArray: Array of Byte);
var MS: TMemoryStream;
begin
  MS := TMemoryStream.Create;
  try
    MS.WriteBuffer(ByteArray[0], Length(ByteArray));
    MS.Seek(0, soFromBeginning);
    aBMP.LoadFromStream(MS);
  finally
    MS.free;
  end;
end;
// Utilisation
procedure TForm1.Button2Click(Sender: TObject);
begin
  ByteArray2Bitmap(Image2.Picture.Bitmap, aBArray);
end;