Hello Tina,
Happy to know that you are using Infinite Photography. Based on your question, we have only two type of layout on free version of theme. We are soon going to launch the premium version of this theme with lots of additional features and obviously masonry layout will also there. Please wait some days, we will be here with awesome theme, Infinite Photography Pro.
If you want to add this functionality on free version, you have to do some customization work.Prepare a child theme and customize the theme as your need. If you are familiar with WordPress codes, you can easily integrate on free version too. But we highly recommend you to use pro version of theme. If you have any further query, please write us. We will do our best to solve your problems.
Best Regards,
Acme Supports