In the Main Settings Tab find Gallery Type section and turned on Vertical Type. You can set width in pixels or percents for Vertical Gallery Type, photo height proportions will be changed automatically.
If you have set width in percents, photo height will be changed automatically, accordingly to original size proportions. If you established width in pixels, the height of the photo will be transformed accordingly to original size proportions.
Thus you can take photos with different sizes and they will look great with Vertical Type of the gallery.
For instance —