Nice job. Also enjoy slide puzzles so I built something similar a few months back.

I compute the different grids (4x4, 3x3, 3x5) according to the aspect ratio of the uploaded image so it works with landscape and portrait style pictures.

https://slide-puzzles.specr.net

I built Puzzme out of pure nostalgia. Growing up, I loved those physical 3x3 sliding puzzles. After recently resigning from my career as a process engineer, I finally found the time to recreate that experience for the web.

As a kid, once I solved a 3x3 puzzle, the only way to get a new challenge was to buy a different version with new art. Now, using what I’ve learned in web development, I’ve made it so anyone can turn their own gallery photos into a custom puzzle.