The preview on a photo-mosaic sales page is too small to tell you anything that matters. It can’t show you whether the tiles are real photos or a tinted shortcut, whether the faces came through whole, or whether it will hold up at the size you want to print. All of that lives in the close-up, and most services only hand you the close-up after you’ve paid.
So that’s what this guide is for: reading a mosaic before you own one. We make these, so we know where the corners get cut. Here’s what to look for, whoever you end up choosing.
Overlay
There are two ways to build a mosaic. The honest way matches each of your photos to a patch of the target by color, and lets the picture emerge from real photos. The shortcut builds a rough version and drops the target image over the top at low opacity, like a film of tinted glass. From across a room, both pass. But the shortcut stains every photo you sent. Lean in, and your trip to Lisbon, the birthday, the dog, all of it is wearing the same dull wash.
We don’t use overlay. Not on one tile. If a service won’t say whether they do, assume they do.
To see it yourself, ask for a full-size close-up. Real tiles look like a wall of tiny, true-colored photographs. Overlaid tiles look like one photo behind a colored window.
Cropping: do faces survive?
Your photos are rectangles; the grid wants squares. Something gives. Cheap tools crop straight from the center, so faces lose their tops, the way a photo booth clips you when you sit too tall. Better systems find the face first and crop around it. Ask which a service uses. With the cheap kind you won’t notice until it’s printed and half your portraits come back trimmed at the hairline.
Resolution: printing big
A mosaic earns its keep up close, which is exactly where a weak file falls apart, the tiles softening into blocks. Before you commit to a size, ask for the pixel dimensions of the final file. Ours run 12,800 by 9,600, which holds well past poster size.
How many photos you’ll need
More photos, less repetition. Most services want at least 300, and below that the same few faces start surfacing all over the picture. Variety counts as much as number: 300 photos from different days and different light beat 1,000 taken on the same couch. (We ask for 300 and set no ceiling. The full math is in our guide on how many photos you need.)
File, print, or both
The digital file is the flexible, affordable option: print it anywhere, keep it on a screen, send it to family. A poster, canvas, or framed print arrives ready to hang. Check the materials and the sizes either way. (Ours start at $179 for the file. Order a print and the high-resolution file comes with it.)
The photos that have to be in it
Some photos aren’t optional. The portrait of the person this is for. The dog who isn’t around anymore. Good services let you mark a few as must-use, so the algorithm can’t quietly drop them for not matching a color cleanly. If you have photos like that, and most people do, ask whether it’s allowed. (We allow it.)
The close-up test
Before you pay anyone, ask to see a single full-size close-up of a real finished mosaic, not a marketing render. In that one image you can read the overlay, the cropping, and the sharpness at a glance. A service that’s proud of its work sends it without hesitating. A service that hesitates has just answered the question.
That’s the guide. If you want to see how we answer each of these, our work is here. Whoever you choose, get the close-up first.