Use the free Stained Glass Photo Effect below: upload a photo, adjust the settings, and download your result as a PNG. Your image never leaves your browser — all editing happens on your device, and nothing is uploaded to any server.
What Is Stained Glass Art?
Stained glass windows are made of small pieces of coloured glass joined by dark lead lines. Light shines through the glass, so each piece glows with its own colour, and the lead lines draw the shapes. Churches, old houses and public buildings have used them for centuries, and the style is still loved for its colour and craft.
The Stained Glass Photo Effect turns your photos into that style. It divides your photo into irregular glass pieces, fills each piece with the photo’s colour in that area, and outlines every piece with a dark lead line. The result looks like a window made from your photo.
How the Effect Works
The tool uses a mathematical idea called a Voronoi diagram. It scatters seed points randomly across your photo. Every point owns the region of the photo closer to it than to any other point. Those regions are the glass pieces: irregular polygons that fit together without gaps, just like cut glass.
The geometry is computed by the d3-delaunay library, a well-tested open-source tool for Delaunay triangulation and Voronoi diagrams, loaded from a public CDN. The tool builds the triangulation from the seed points, derives the Voronoi cells, and then, for each cell, averages the photo colours inside it. That average becomes the cell’s glass colour.
Averaging matters. If each cell were filled with a single pixel’s colour, the result would look speckled. Averaging over the cell gives a smooth, glassy colour that still follows the photo: a blue sky region becomes blue glass, a red flower becomes red glass. Finally the tool strokes every cell with a dark outline, the lead came, at the width you chose.
More pieces mean smaller glass and more detail. Fewer pieces mean large bold panes and a simpler, more abstract window. The outline width changes the feel too: thin lines look delicate, thick lines look like a heavy old window.
How to Use It
Upload a photo. Colourful photos with large shapes work best: flowers, landscapes, portraits with strong colours. The stained glass version appears at once with 220 pieces. Try 100 pieces for a bold, simple window, or 400 for a detailed one. Very high counts can be slow on older devices, so raise the count gradually.
Change the outline colour if you like: near-black is classic, but dark brown suits warm photos. When you are happy, press Download PNG. Because the seeds are random, pressing Apply again gives a different arrangement of pieces from the same photo, so you can pick your favourite layout.
Tips for Beautiful Glass
Choose photos with big colour regions. A red rose on green leaves, a sunset over water, a bright building against sky. Those translate into clear glass colours. A photo that is mostly one colour, like a foggy grey scene, becomes mostly one glass colour, which is less interesting.
If the result looks too busy, lower the piece count. Large panes read as glass from a distance. If it looks too simple, raise the count until the subject’s features appear. Faces need higher counts than landscapes, because facial features are small.
Where to Use Stained Glass Photos
Stained glass versions of photos make lovely posters, greeting cards and craft patterns. Some people use them as a starting point for real glass work or for colouring pages: print the result, and each cell is a region to fill. They also make distinctive social posts and phone wallpapers, because the lead lines and flat colours stand out.
Privacy
Your photo never leaves your browser. The Voronoi geometry and colour averaging run on your device. The d3-delaunay library is code, not a service: it does not receive your photo. Nothing is uploaded, stored or shared, and no account is needed.
Frequently Asked Questions
Why does the layout change each time? The seed points are random. Each run scatters them differently, so the pieces change. Run it again until you like the layout.
Why is my result slow? High piece counts mean many cells to average. Lower the count or use a smaller photo.
What if the library fails to load? The tool will tell you to wait a moment and press Apply again. Check your connection and retry; the effect needs the d3-delaunay script from the CDN.