GitHub

Turn a thousand photos into one big one.

Nothing is uploaded

Drop in your pictures, pick a face or a view for the big picture, and get a poster file your print shop can use. It works on your own computer or phone.

Make a poster See the code

Your photos stay in this browser tab. HEIC and camera RAW files are fine. This web version makes RGB files (PDF or JPEG).

A finished demo mosaic poster: a red heart under a pale sun, built from 600 small generated pictures.
The demo poster, built from 600 generated pictures. Move over it to look at the little photos. Inside the dashed box you see the real close-up; elsewhere the loupe only enlarges this picture.

One photo in. One poster out.

The target picture: a heart at sunset.
1. The big picture A simple, bold picture reads best.
The finished poster.
2. The poster 600 generated photos, 40 tiles across, 18 x 24 in at 200 DPI.
3. Up close Real pixels from the 200 DPI file: 4.5 x 3 in of the print, each tile its own photo.

The demo uses generated pictures, not real photos. The repo's examples/make_demo.py rebuilds it.

  1. 1Throw in all your photos. Folders, zips, phone exports, the lot.
  2. 2Pick the big picture. A big, well-lit face works best.
  3. 3Check the preview on your printer's paper, then download the PDF.

Pick your printer first

Example Checks (plotter on bond paper, 40 in wide, 150 DPI)

  • error
    40 in is wider than this printer's 36 in maximum
    Fix: Use 36 x 54 in
  • warn
    150 DPI is below the 300 DPI this printer wants
    Fix: Set quality to 300 DPI

RGB only on the web. This page makes RGB files, which most shops convert. CMYK output needs the command-line tool.

1 Your photos

No photos handy? Fills every step with made-up ones.

Drop photos, folders or .zip files here JPEG, PNG, HEIC, WebP, AVIF, TIFF, camera RAW. Drive and iCloud zips work as they are.

No photos yet.

2 The big picture

Your big picture shows here

Click the picture to choose the centre. A large, well-lit face works best.

3 Printer and size

4 The look

Colour for print

Preview

Your poster will appear here.This is the demo, not yours. Add photos and a big picture, or fill it all in one click.

Up close: 6 x 4 inches of the print at actual size
Magnified 3x

Checks and recommendations

    5 Download

    Unlocks when your poster preview is ready.