How to make a nine-grid photo post
Split one image into a 3×3 grid, then upload tiles left-to-right, top-to-bottom so the feed reassembles the full picture.
A nine-grid post is simply nine equal tiles of one image, uploaded in reading order.
If the source is not square, use “crop to square first” so each tile stays square.
Download the ZIP and upload 01→09 in order. Processing stays on your device.