Cutting notes

The tool settles the arithmetic — where each boundary falls, which column keeps the spare pixel, what every tile measures before a byte is written. These notes cover the half it cannot settle: what happens to the pieces once they leave this machine.

The first two are written against the profile grid, because that is where the tiles from this site mostly go and because it is the destination that re-encodes them. None is a tour of the interface. If a note tells you to change the framing rather than the grid, that is the finding, not a preamble to one.

The notes, in the order you need them

• A grid that survives the feedWhere to leave room before the cut, measured against the gutter the profile draws and the compression the platform applies on its way in.Read it before you frame the picture.
• Posting order for a nine-tile gridWhy nine tiles go up in reverse, what a stray post in the middle of the sequence does to the arrangement, and how to rescue a grid that is already three tiles in.Read it after the ZIP has landed.
• Carousel splits and the swipe seamWhere the boundaries of a 2- to 20-slide carousel fall on the picture, and how to keep a subject off them.Read it before you choose the number of slides.
• Print a poster across A4 sheetsMargins, overlap, trim marks, the poster PDF and what to tell a print shop.Read it before you press print.
• DPI and how big a split image can printPixels divided by printed inches, and why a DPI label adds no detail.Read it before you choose the number of sheets.
• Why one tile is a pixel narrowerThe three remainder rules, with numbers computed by the splitting engine itself.Read it when the sizes in the index surprise you.
• PNG or JPEG for split tilesWhat each format does to the seams when tiles are put back together, measured.Read it before you choose the tile format.
• Scanning several photos at onceLaying prints on a flatbed so each one is found and straightened automatically.Read it before the first scan.

What the board refuses

Joining tiles back into one picture, guessing where a face is, and squeezing a set of tiles into a kilobyte budget are refused on purpose; the one place a file-size target applies is the photo-and-signature page, where a notice states one per file. The reasoning is on the front page, which is a shorter read than a guide pretending otherwise.