Two ways to split an image
Into rows and columns
Choose how many pieces you want, such as 3 × 3 or 2 × 4, and the image is divided into equal parts. If its size doesn’t divide exactly, some pieces are one pixel larger so none of the picture is lost.
Into pieces of an exact size
Enter a size in pixels, such as 1080 × 1080, and the image is cut into as many pieces of that size as fit. Any strip left over at the right or bottom edge is shown in the preview and left out.