how do I make a PDF of a photo in an iphoto album

What do you mean by iPhoto Album? Do you mean an album which you created in an iPhoto Library?

Or do you mean a photo book created in iPhoto?

which looks like these.

You can create a PDF file of a photo by starting to print it and use the PDF ➙ Print to PDF option:

You can do it from any application.

How do you make a pdf from a photo?

Start the print process to print whatever size photo you'd like and use the Save as PDF menu in the print window.