About
Marcus Cedergren
Software developer & amateur photographer
I built Collage Studio out of personal frustration. I couldn't find a collage tool that handled large sets of photos the way I wanted. Every app or service I tried either forced my images into a fixed template or produced rigid, predictable grids, often cropping images to make the images fit the layout instead of the other way around. Many were slow to work with too, and uploading personal holiday photos to services I knew nothing about never felt safe. I wanted something that arranged photos organically, filling the canvas as completely as possible, giving each image the space it deserved, and producing a high-resolution file good enough to send straight to a print shop for a large poster. Being a software developer, the obvious solution was of course to just build it myself!
What it does
Most collage tools drop your photos into a fixed template or a rigid grid. Collage Studio works differently: it arranges each set of images to fill the canvas as completely as possible without following a preset template, so every result looks different.
Because it solves for the arrangement rather than following a template, it handles large sets well (up to 300 images). You can give a few images a weight to make them larger and more centrally placed. The more photos you add, the more combinations the solver has to work with.
Export as a 300-DPI print-ready file at standard paper sizes, or sized for your screen or social media: square and portrait posts, 9:16 stories and reels, short-video formats, pins, and profile covers and banners for all major platforms.
Everything runs in your browser. The layout algorithm is compiled to WebAssembly and runs locally on your device's CPU. No uploads, no accounts.
How it works
When you create a collage, the app explores a large number of possible arrangements and keeps the one that fills your chosen size most completely while respecting any images you've given a weight. The search runs in parallel across your device's CPU cores, so even large image sets usually finish in seconds.
Each run usually finds a new arrangement, so you can regenerate until you're happy with the result. The algorithm adjusts automatically to your image count and size.
The layout engine is a genetic algorithm, the same family of techniques used to solve complex optimisation problems in engineering and logistics. It starts with a population of random arrangements and evolves them over hundreds of generations: layouts that fill the canvas well survive and pass on their traits, while poor ones are discarded. Small random mutations keep the search from getting stuck. The aim is a near optimal arrangement, found through guided exploration rather than brute force. That is why runs usually differ, and why more images give it more to work with.
The basic idea, a recursively divided canvas searched with a genetic algorithm, comes from Jian Fan's 2012 paper Photo Layout with a Fast Evaluation Method and Genetic Algorithm.
Tips
- 1
Use 15 or more images for best results. More images give the algorithm more to work with.
- 2
Tap any image and set a weight (×2, ×3, or ×5) to give it more space and a prominent position in the collage.
- 3
If the result has gaps, try a different size or add more images. Each run usually finds a new layout, so generating again often closes remaining gaps.
- 4
Save results you like before generating again. Each run is different, so the same layout is unlikely to come up again.
Contact
I hope Collage Studio comes in handy, whether it ends up as a print on the wall or a post in your feed. Feel free to get in touch with questions, a thumbs up, ideas for improvements, or anything that doesn't work as it should. You can reach me at collage-studio@kodverket.se.