imported photos improperly cropped

When I make a movie (or I slide show in iMovie for iPad. Frequently when I import a potograaph from photos, the picture is partially cropped by iMovie. There are parts that can’t be seen. When I do it on the computer version it all turns out FINE. Am I doing Something wrong? The pictures are the original pictures taken with my iPad . I am using the most up-to-date of all software and I have the 12.9 inch iPad Pro . Please help!