The Template Creator is available to automatically adjust both the size of a template to a user photo, and the size of a user photo given the size of a template.
The resulting size depends on the type of a template. When using templates of the "Filter" and "Sticker" type, the resulting size will be equal to the size of a user photo. In other template types the resulting size will depend on the canvas size set in Photoshop. You can find more info on this feature by following this link.
Also, the template creator allows you to configure the automatic change of the template graphics according to the orientation of a user photo. Learn more about this option here.