Where is the setting to increase the size of the single portfolio image? Or more preferably, where the image gets cropped from. Currently it’s cutting off half the faces in the featured images (even Landscape images) as I presume its cropping from the middle. Can it crop from the top, or increase the height of the single image?
If you are concerned about cropping in the pages that display multiple portfolio items, the best way is to upload an image which is already cropped appropriately by you in a photo editing tool instead of relying on the system to do it. Changing height of images in these pages will spoil the layout and make the whole arrangement look odd. Hope this helps.