Small Photo Printers Hp Photosmart 375 How Do I Print On Small Photo Paper?

How do I print on small photo paper? - small photo printers hp photosmart 375

My HP Photosmart printer has a smaller place to on photo paper the same size as him the place, but how can I do?

I have the A4 and smaller paper, but how can I choose not to print on A4? How do I choose?