Inputs

• Two or more absolute paths to local input images
• Optional output path; default to an explicit

  collage.png

  in the current working directory
• Optional canvas size (

  --width

  ,

  --height

  ), default

  1920×1200

• Optional

  --seed

  for deterministic layout

Prepare Instructions

• Shell environment variables
• The current working directory

  .env

  only

• ~/.transloadit/credentials

.env

Run

npx -y @transloadit/node image merge \
  --input ./photo-a.jpg \
  --input ./photo-b.jpg \
  --input ./photo-c.jpg \
  --input ./photo-d.jpg \
  --input ./photo-e.jpg \
  --input ./photo-f.jpg \
  --effect polaroid-stack \
  --width 1920 \
  --height 1200 \
  --format png \
  --output ./collage.png

Tuning

• --background '#eee5d3'

  picks a warm beige canvas (default). Hex codes or named colors both work.

• --background none

  (with

  --format png

  or

  --format webp

  ) produces a transparent canvas.

• --coverage 1.5

  is the default. Use

  2.0

  –

  2.5

  for bigger, more overlapping photos;

  1.0

  or below for smaller, more widely spaced polaroids.

• --seed 42

  makes the layout deterministic — rerun with the same inputs to reproduce the same output.

• --shuffle

  lets the Robot reorder inputs before laying them out.

Debug If It Fails

npx -y @transloadit/node assemblies get <assemblyIdOrUrl> -j

• Repeated

  --input

  values are bundled into a single

  /image/merge

  assembly.
• The polaroid-stack effect works best with 4–12 inputs. Fewer than four tends to look sparse; more than a dozen starts to occlude heavily.
• Each input is cropped to a square inside its polaroid frame — portrait or landscape originals both work.
• Prefer an explicit output filename (e.g.

  ./collage.png

  or

  ./collage.jpg

  ) over a directory output so the extension is deterministic.