Custom image block

VCL TMS Diagram Studio
2

Dear members,

I found the solution:

with atDiagram1.Blocks[0] do
begin
  Shape := bsNoShape;
  Bitmap.LoadFromFile('myBitmap.bmp');
end;

But I've got a error message when loading a .png file ...

with atDiagram1.Blocks[0] do
begin
  Shape := bsNoShape;
  Picture.LoadFromFile('myPNG.png');
end;

ERROR MESSAGE:
Unknown picture file extension

What causes this ERROR ?

Thanks.