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Photo Mosaic Maker
A photo mosaic is a big picture built out of many little ones: stand close and you see dozens of small photos; step back and they become one large image. This free maker builds one in your browser. Give it a main photo and up to 50 small tile photos, choose how fine the grid should be, and it matches every cell of the main photo with the tile whose average colour fits best. No tile photos handy? Use Colour blocks mode — it paints each cell with the photo's own average colour, a clean pixel-mosaic effect that needs no tiles at all. Your photos are never uploaded.
Everything happens on your device — your photos are never uploaded. Big grids (80–100 columns) with many tiles can take a while and use a lot of memory; start at 40 columns to see the effect quickly.
How to use this photo mosaic maker
- Choose the main photo — the picture the mosaic should become. Portraits and strong, simple shapes work best.
- For Tiles mode, choose up to 50 small photos to build it from. A varied set — different colours and brightness — gives the best match. For Colour blocks mode, skip this step.
- Set the grid columns. 20 is quick and chunky, 40 is a good start, 80–100 is fine and detailed but slow.
- Press "Build mosaic" and watch the progress line. When it finishes, press "Download PNG" — then view the mosaic from a distance, or zoom out, to see the main photo appear.
How the mosaic is built
The tool divides your main photo into a grid of cells. For every cell it works out the average colour — all the pixels in that cell blended into one shade. In Colour blocks mode, that shade simply fills the cell. In Tiles mode, the tool first finds the average colour of each of your tile photos, then for every cell picks the tile whose average colour is closest to the cell's shade (comparing the red, green and blue difference) and draws that tile into the cell.
Two honest notes. First, the match is by average colour only — the tool does not look at shapes inside a tile, so a tile with the right shade but a busy pattern can look odd up close; mosaics are meant to be viewed from a few steps back. Second, fine grids are genuinely heavy work for a browser: a 100-column grid means thousands of cells and a large final picture, so it can take a while and may strain an old phone. Start coarse, look, then go finer.
Worked example
For their parents' anniversary, Kavita wants one portrait of the couple built from family photos. She chooses a clear portrait as the main photo (1,600 × 1,200 pixels), adds 32 family photos as tiles, and sets the grid to 40 columns. The tool works out a 40 × 30 grid — 1,200 cells — finds each cell's average colour, and places the closest-matching family photo in every cell. Up close the mosaic is a wall of family moments; from across the room, it is unmistakably her parents' portrait. She downloads the PNG and has it printed.
Choosing the grid size
| Columns | Look and speed |
|---|---|
| 20 | Very blocky, almost instant — good for a first try and for logos |
| 40 | Clear mosaic effect, still quick — the recommended start |
| 60 | Finer detail, noticeably slower |
| 80 – 100 | Finest detail; slow, large PNG, best on a computer with a simple main photo |
Frequently asked questions
How many tile photos do I need?
The tool accepts up to 50. Around 25–50 varied photos give good results: the more shades and brightness levels your tiles cover — dark, bright, skin tones, sky, greenery — the closer each cell's match. With only a handful of tiles the same few repeat everywhere and the main picture gets harder to see. Colour blocks mode needs no tiles at all.
Why does my mosaic look wrong when I zoom in?
That is how mosaics work. Each cell is matched by its average colour alone, so up close you see the individual tiles — a birthday photo standing in for a patch of blue sky, for instance. Step back, shrink the picture, or squint: the main photo appears. If it still does not appear, use more columns, more varied tiles, or a main photo with stronger contrast.
Are my photos uploaded anywhere?
No. The main photo and the tiles are read and processed entirely in your browser on your device, and the finished mosaic is created there for download. Nothing is sent to a server — which is also why very large grids depend on your device's memory and patience.
How big is the downloaded PNG?
The mosaic is at most about 1,600 pixels wide, with the height following your photo's shape — big enough for sharing and for a modest print. At fine grids the file can be several megabytes. If you need a wall-size print, build the finest grid your computer manages and print from that PNG.
What makes a good main photo?
A clear subject, strong contrast and a simple background: portraits, a pet, a house, a logo. Busy scenes with lots of small detail dissolve into noise at small grid sizes. Cropping tightly on the subject before you start helps a lot.
Why is the build slow at 100 columns?
A 100-column grid on a wide photo is around 7,500 cells, and each cell means colour maths plus drawing a tile — and the final canvas is large. The tool works through the grid in chunks and shows progress; on a phone it can still take minutes. 40 columns gives most of the effect in a fraction of the time.