I have always taken the Windows way of printing multiple images and photos (on the same sheet) for granted but when I wanted to do the same from my Mac I quickly realized I didn’t know how. So, for future reference, here it is.
Open all the images or photos you want to print in Preview (in the same Preview window). In Preview’s sidebar, select all images You want to print (or click inside the sidebar and press cmd-A). Go to File→Print… The following dialog will appear (I will soon explain the markings):
First, under “Pages”; select “Selected images in Sidebar”. Next comes the perhaps not so obvious part; In the drop-down list, select “Layout”. Set “Pages per Sheet” to 2 (or more, Your choice). Click “Print” and You’re done.
While you’re here, take a look on how baking a computer in the kitchen oven actually can fix it.