Is it possible to create a pdf file with multiple sizes?

Hi !
I wonder if there is a hint to use multiple page sizes in a pdf document ? (for example, the document’s first page with the whole cover of a book - including the front, the back and the spine)
The pdf format can manage that, that but I can’t find a way to get it using the library.

I don’t think so.
The best is to create .jpg or .png from P5 with the different size.
After you can use a small tool like PDF arranger on linux.
If the name of image are writted in order (001.png, 002.png, 003.png, …), it’s very easy to create the pdf.