Quarters are the obvious answer, not always the good one
Four square gives every picture the same weight, which is exactly right when the four belong together — four dishes, four rooms, four angles on the same object. It is less right when one of the four is the reason you are making the collage at all, because a grid has no way of saying so.
The three uneven layouts each say it differently. A lead picture with three down the side keeps one photo at nearly seventy per cent of the width. A wide band across the top with three underneath treats the first as a scene and the rest as details. The uneven four gives two slots a little more room than the others without any of them being obviously the star, which is the gentlest of the three.
| Layout | Largest slot | Smallest slot |
|---|---|---|
| Four square | 522 × 522 | 522 × 522 |
| Four slices | 255 × 1056 | 255 × 1056 |
| One large, three along | 716 × 1056 | 334 × 346 |
| Wide top, three under | 1056 × 480 | 344 × 564 |
Portraits, landscapes and the mix
Every slot crops what you put in it, because the picture always covers the slot — that is what stops a corner going blank. A portrait photo in a wide slot therefore loses its top and bottom, which is usually fine for a person and disastrous for a building.
Two rules save most of the trouble. Put your tallest photo in the tallest slot, which on three of these five is the left-hand lead. And when a crop takes something you wanted, tap the slot and drag the picture up or down inside it before you go looking for a different layout — nine times in ten the framing was the problem and not the arrangement.
Four in a story shape
Down a 1080 by 1920 story, the even four becomes four full-width rows rather than a two-by-two, because a quarter of that frame is 540 by 960 and two of them side by side leave a collage that reads as a tall sandwich. Four slices stays four slices, which at 270 pixels wide is a deliberate filmstrip rather than an accident. Switch shape in the rail and the strip redraws so you can see it before you commit.