If you use Lightroom I’ve come across a quick and easy way to create a template in the Print module that make PDIs from landscape or portrait format images. Forgive me if you already know about this.
I’ve documented this in a pdf file which I’ve uploaded under the ‘Resources’ tab. It’s an easy step by step process to create and save the template. You can of course choose your own settings if you prefer. Once the template is exists, select your image in the Library module, switch to the Print module and select the template, then save the PDI to where ever you choose. Let me know if you have any problems with it.