What this tool does
Photo Collage Maker composites several decoded images onto one raster canvas and encodes PNG, JPEG, or WebP.
When to choose it instead of a similar DevToolKit tool
- Use this for a single grid image.
- Use Image to PDF for one image per PDF page.
- There is no free-form drag layout beyond the five presets.
Typical jobs this page is built for
- Build a 1200×1200 4-grid (the default layout and Square canvas).
- Make a 1080×1920 Story collage with Cover cropping.
- Export PNG when you want the collage without JPEG quantization; use JPG when the destination wants JPEG.
Supported inputs, limits, and output behavior
- Inputs
- JPEG, PNG, WebP, GIF, BMP; 20 MB each. No separate MAX_IMAGES constant.
- Canvas
- Square 1200×1200, Portrait 1080×1350, Story 1080×1920, Landscape 1600×900.
- Quality
- JPEG/WebP slider min 60, default 92, clamped 0.5–1 on encode. PNG omits quality.
How the transformation actually works
loadCollageItems uses Image + object URLs. renderCollageToCanvas fills the preset size, then drawImageInSlot per cell. GIF/WebP animation is not preserved as animation.
Step-by-step workflow
- Click Choose photos or drop files.
- Pick a layout.
- Reorder with Move earlier / Move later.
- Pick a canvas size.
- Pick Cover, Contain, or Stretch.
- Set Gap and Background.
- Pick PNG, JPG, or WebP, then Quality if it appears.
- Edit File name if you do not want the default.
- Click Create collage.
- Check each cell in the download.
What can change in the output
Cover crops. Stretch changes aspect. JPEG flattens the whole canvas including the background fill. Cell images are resampled to slot size.
Known limitations and failure cases
- Corrupt files marked error.
- NO_IMAGES if nothing usable.
- EXPORT_FAILED on empty blob.
- No per-cell zoom beyond fit mode.
Privacy / where data goes
Composition runs in the browser. The privacy line on the upload panel notes that usage/diagnostic metadata may still be sent. Identified analytics may include file counts, canvas preset, layout, and output format, not the photo pixels.
Practical output-review checklist
- Confirm which photos landed in which cells; only the first layout.count ready images are drawn.
- Check Cover cropping of faces.
- If JPEG, confirm the gap color matches backgroundColor.
- Open the download at the canvas pixel size (Square 1200×1200, Portrait 1080×1350, Story 1080×1920, Landscape 1600×900).