Yoga Studio is great for yoga lovers, I’m glad you mentioned it. The classes are so varied and really help you reach that state of relaxation.

This is definitely an interesting tool to crop images. But there are alternatives as well that get the job done quite effectively.
Another good option for me is BatchPhoto Espresso. It’s a free online photo editor that enables you to not only crop, but also resize, convert or rotate multiple images at once.

Preview is definitely an option to consider for batch resizing on a Mac. I would also recommend PhotoMarks, since its more powerful and also allows you to watermark images in batch mode.