A grid split is what you want for turning one picture into a 3×3 Instagram puzzle or a set of equal tiles for a print layout. Strip mode in Image Splitter cuts the picture into equal columns or rows instead, which is the usual way to slice a wide banner or a long infographic for a website.
Split a panorama into carousel slides
A swipeable carousel looks seamless when one wide photo is cut into equal vertical strips. Choose Vertical strips and set the columns to the number of slides. For three 4:5 portrait slides, start from an image 2.4 times as wide as it is tall.