Why a simple grid collage still needs a dedicated tool
Combining six vacation photos into one shareable image, or putting a week's worth of progress photos side by side, sounds like it should take thirty seconds. In practice, doing it in a general design tool means creating a canvas, manually placing and resizing each photo, fixing the gaps between them, and making sure nothing ends up stretched or off-alignment — twenty minutes of fiddling for what's conceptually a simple grid.
A dedicated collage tool skips all of that setup: add your photos, pick a column count and spacing, and get one evenly-arranged image back — no canvas sizing, no manual placement, no eyeballing alignment.
How photos actually get to fill a grid cell without gaps or stretching
The reason your photos don't come out squished or leaving empty space in their cells is a technique called cover-fit cropping: each photo is scaled up or down until it completely fills its assigned cell, and whatever spills over the edges gets cropped away. This is the same logic behind how thumbnail grids work on nearly every photo app and social platform — prioritizing a clean, fully-filled cell over showing every pixel of the original photo.
The trade-off worth knowing: since excess content gets cropped rather than shrunk to fit, a photo with an important subject near the edge of the frame might have that subject partially cropped out if its aspect ratio doesn't closely match the grid cell's shape. For photos where edge content matters, it's worth a quick crop beforehand to center the subject.
Mixing portrait, landscape, and square photos in one collage
One thing that trips people up in DIY layout attempts: mixing photos of wildly different aspect ratios (a tall portrait shot next to a wide landscape) usually means either stretching one to match the other, or ending up with visibly different cell sizes that break the grid's clean look. Since every cell here is a fixed, uniform shape and each photo gets cover-fit cropped into it regardless of its original proportions, you can freely combine phone portraits, wide landscape shots, and square Instagram-style photos into one consistent-looking grid without any manual reconciliation.
Order and odd numbers — what to expect
Photos fill the grid in the exact order you add them, left to right and top to bottom — if the arrangement doesn't come out how you pictured it, the fix is re-adding photos in the order you actually want rather than looking for a drag-to-reorder option that doesn't exist here. And if your photo count doesn't divide evenly into your column count, the last row just ends up with fewer filled cells instead of forcing an awkward uneven layout — a collage of 7 photos in 3 columns simply leaves the last row with one photo instead of three, which looks intentional rather than broken.