What does "Transpose" mean?
Transposing a grid means swapping the axes. The sprite at Row 1, Column 2 moves to Row 2, Column 1. Imagine taking a grid of items and flipping it diagonally.
Why is this useful?
Game Development: Some game engines read sprite sheets "Row by Row", while others read them "Column by Column". This tool allows you to convert an asset pack to match your engine's requirements without manually cutting and pasting 64 individual images in Photoshop.