File > Automate > Photomerge will create a panorama. Is that what you are looking for?
Thank You Benjamin, but your kind answer is not what I want.
I have no problems with creating panoramic photos, even with 60 or more pictures.
But how could I do a sandwich fusing 2 pictures of the same size ?
So, like an HDR? Could you explain what you're looking to achieve? I'm afraid I don't know what you'd like to do just yet.