Unite gallery


I am using the shapely theme for my wordpress blog which mostly presents photos, no texts. For presenting and organizing the photos I installed the Unite gallery. The Unite gallery shows the pictures in small previews, always two pictures in one row. The preview-pictures open up in full size when clicking on them. Now I have the problem that all preview-pictures are in landscape format. How can I change them to portait format in just one gallery? Can I change the preview-options seperately for each gallery?

Thank you for giving advice!