How do I post the tiles so they reassemble into one picture?
Upload them in the numbered order shown on the preview. The downloaded files are already zero-padded in that order (01, 02, 03…), so sorting by name in your gallery or file manager gives you the right sequence. Worth knowing: feeds lay tiles out by the order you added them, not by filename — so when picking them one at a time, go from the lowest number up.
Why is “crop to square first” recommended?
Because grid thumbnails are displayed as squares. If you slice a rectangular image into nine rectangular tiles, each tile then gets center-cropped to a square by the platform, every tile loses a different sliver of content, and the seams no longer line up. Cropping to a square yourself first means every tile is already square, the platform leaves them alone, and the grid reassembles seamlessly. If your image is already square, the option makes no difference.
Does slicing reduce image quality?
PNG output is completely lossless — slicing just separates pixels by position, with no re-encoding. JPEG output adds one lossy compression pass (much smaller files, and usually indistinguishable for photos). Either way each tile is cut at the original resolution with no downscaling, so the reassembled grid is exactly as sharp as your source.
Is my image uploaded to a server?
No. Slicing and zipping both happen inside your own browser, so the image never leaves your device. You can even go offline and keep using this page.