Printing photos

3rdajn wrote: I would like to print a portrait photo in landscape.

If you want to crop the picture, that is, cut off the top and bottom, then you can choose Edit and Crop to cut it to whatever shape you like, including some standard ones.

If you want to print a vertical picture sideways on a piece of paper, then you can select the image and use File>Print ( ⌘-p ) and select from choices like these:

What sized print do you want to print and on what sized paper?

Is it something like this?