create-collage-from-images.md

🖼️ Collage Script

collage.sh is a simple command-line tool to generate a uniform photo collage from all images in the current directory.
It uses ImageMagick under the hood (montage command).

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✨ Features

• Works with JPG/JPEG/PNG images (case-insensitive).
• Automatically detects the number of images and creates a near-square grid.
• Resizes all images to uniform cells while preserving the full image (adds padding as needed).
• Adjustable thumbnail size and output filename via CLI arguments.
• Default background color is white (can be changed in the script).

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📦 Requirements

• ImageMagick must be installed.

Install on:

• macOS:

  brew install imagemagick

• Ubuntu/Debian:

  sudo apt-get install imagemagick

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🚀 Usage

1. Save the script as collage.sh

2. Make it executable:

   chmod +x collage.sh

3. Run it in a folder containing your images:

   ./collage.sh

Arguments

./collage.sh [SIZE] [OUTPUT]

• SIZE → (optional) cell size for each image, e.g. 300x300 (default: 300x300).
• OUTPUT → (optional) output file name (default: collage.jpg).

Examples

• Default:

  ./collage.sh

  → Creates collage.jpg with 300×300 image cells.

• Custom size:

  ./collage.sh 400x400

  → Creates collage.jpg with 400×400 cells.

• Custom size + output filename:

  ./collage.sh 400x400 mycollage.png

  → Creates mycollage.png with 400×400 cells.

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📝 Notes

• The grid size is automatically chosen based on the number of images.
• Images are resized to fit inside the chosen SIZE while keeping their full content visible.
• Empty space is padded (default: white). Change -background white in the script if you prefer black or transparent.

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✅ Example Output

If you have 9 images in a directory and run:

./collage.sh 300x300 collage.jpg

You’ll get a neat 3×3 collage, with each image scaled to fit a 300×300 cell.

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📜 License

MIT – feel free to use and modify.

create-collage-from-images.sh

#!/usr/bin/env bash
# collage.sh - Create a uniform collage of images in the current directory
# Requires: ImageMagick (montage command)

set -euo pipefail

# Default values
SIZE="${1:-300x300}"         # Thumbnail size (each cell)
OUTPUT="${2:-collage.jpg}"   # Output file

# Find all images (jpg, jpeg, png) in current dir
IMAGES=(*.{jpg,jpeg,png,JPG,JPEG,PNG})
if [ ${#IMAGES[@]} -eq 0 ]; then
  echo "❌ No images found in the current directory."
  exit 1
fi

# Count images
COUNT=${#IMAGES[@]}

# Compute grid size (near-square)
COLS=$(echo "sqrt($COUNT)" | bc)
ROWS=$(( (COUNT + COLS - 1) / COLS ))

echo "📸 Creating collage of $COUNT images..."
echo "   Grid: ${COLS}x${ROWS}, Cell size: $SIZE, Output: $OUTPUT"

montage "${IMAGES[@]}" \
  -resize "$SIZE" \
  -background white -gravity center -extent "$SIZE" \
  -tile ${COLS}x${ROWS} -geometry +2+2 \
  "$OUTPUT"

echo "✅ Collage created: $OUTPUT"