macOS Quick Action that adds a random gradient background + drop shadow to images. Supports batch processing — just select multiple files in Finder, right-click, and go. Requires ImageMagick.

gistfile1.txt

#!/bin/zsh

# Add Random Gradient Background + Drop Shadow - macOS Quick Action Script
# Requires: ImageMagick (brew install imagemagick)

export PATH="/opt/homebrew/bin:/usr/local/bin:$PATH"

for INPUT_FILE in "$@"; do
    FILENAME=$(basename "$INPUT_FILE")
    DIRNAME=$(dirname "$INPUT_FILE")
    EXTENSION="${FILENAME##*.}"
    BASENAME="${FILENAME%.*}"
    OUTPUT_FILE="${DIRNAME}/${BASENAME}_gradient.${EXTENSION}"

    # Get image dimensions
    WIDTH=$(magick identify -format "%w" "$INPUT_FILE")
    HEIGHT=$(magick identify -format "%h" "$INPUT_FILE")

    # Generate random colors (hex), avoid near-white (brightness < 200)
    MAX_BRIGHTNESS=200

    while true; do
        R1=$((RANDOM % 256)); G1=$((RANDOM % 256)); B1=$((RANDOM % 256))
        BRIGHTNESS1=$(( (R1 + G1 + B1) / 3 ))
        [[ $BRIGHTNESS1 -lt $MAX_BRIGHTNESS ]] && break
    done

    while true; do
        R2=$((RANDOM % 256)); G2=$((RANDOM % 256)); B2=$((RANDOM % 256))
        BRIGHTNESS2=$(( (R2 + G2 + B2) / 3 ))
        [[ $BRIGHTNESS2 -lt $MAX_BRIGHTNESS ]] && break
    done

    COLOR1=$(printf '#%02X%02X%02X' $R1 $G1 $B1)
    COLOR2=$(printf '#%02X%02X%02X' $R2 $G2 $B2)

    # Random gradient direction
    DIRECTIONS=("0" "45" "90" "135" "180" "225" "270" "315")
    ANGLE=${DIRECTIONS[$((RANDOM % ${#DIRECTIONS[@]}))]}

    # Settings
    PADDING=80         # space around image
    SHADOW_OFFSET=12   # shadow offset in px
    SHADOW_BLUR=18     # shadow softness
    SHADOW_OPACITY=70  # shadow darkness (0-100)

    CANVAS_W=$((WIDTH + PADDING * 2))
    CANVAS_H=$((HEIGHT + PADDING * 2))

    # Create gradient → add shadow to image → composite on gradient
    magick \
        -size "${CANVAS_W}x${CANVAS_H}" \
        "gradient:${COLOR1}-${COLOR2}" \
        -define gradient:angle="${ANGLE}" \
        \( "$INPUT_FILE" \
            \( +clone \
                -background "rgba(0,0,0,${SHADOW_OPACITY})" \
                -shadow "${SHADOW_OPACITY}x${SHADOW_BLUR}+${SHADOW_OFFSET}+${SHADOW_OFFSET}" \
            \) \
            +swap \
            -background none \
            -layers merge \
        \) \
        -gravity center \
        -composite \
        "$OUTPUT_FILE"

    echo "✅ Saved: $OUTPUT_FILE"
    echo "   Gradient: $COLOR1 → $COLOR2 | Angle: ${ANGLE}° | Shadow: offset=${SHADOW_OFFSET}px blur=${SHADOW_BLUR}px"
done

A macOS Quick Action script that adds a random gradient background + drop shadow to any image (or batch of images) directly from Finder's right-click menu. Powered by ImageMagick.

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What it does

• Generates two random colors for the gradient (never near-white)
• Picks a random gradient angle (0°, 45°, 90°… 315°)
• Adds a soft drop shadow behind your image
• Saves the output as a new file (yourfile_gradient.jpg) — original is untouched
• Works on a single file or multiple files at once

---

Requirements

• macOS (tested on Ventura / Sonoma)
• [Homebrew](https://brew.sh)
• ImageMagick

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Step 1 — Install ImageMagick

Open Terminal and run:

brew install imagemagick

Verify it's working:

magick --version

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Step 2 — Create the Quick Action in Automator

1. Open Automator (use Spotlight: ⌘ Space → type Automator)
2. Click New Document
3. Choose Quick Action as the document type
4. At the top of the workflow, set:
   • Workflow receives current → image files
   • in → Finder
5. In the search bar on the left, search for Run Shell Script
6. Drag it into the workflow area on the right
7. In the action settings:
   • Shell → /bin/zsh
   • Pass input → as arguments
8. Paste the script above into the text area

---

Step 3 — Save the Quick Action

1. Press ⌘ S to save
2. Name it: Add Gradient Background
3. Close Automator

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Step 4 — Use it in Finder

1. Select one or more image files in Finder
2. Right-click → Quick Actions → Add Gradient Background
3. Done! A new file named yourimage_gradient.jpg will appear in the same folder

Batch processing works out of the box — select as many images as you want, they'll each get their own unique random gradient.

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Customization

You can tweak these four variables inside the script:

Variable	Default	What it controls
PADDING	80	Border size around the image (px)
SHADOW_OFFSET	12	How far the shadow is offset (px)
SHADOW_BLUR	18	Shadow softness / spread
SHADOW_OPACITY	70	Shadow darkness (0 = none, 100 = solid black)
MAX_BRIGHTNESS	200	Max brightness to allow for gradient colors (lower = darker colors only)

---

Troubleshooting

Quick Action doesn't appear in Finder

• Make sure you set "Workflow receives current → image files in Finder" in Automator
• Try logging out and back in, or restart Finder: killall Finder

magick: command not found

• The PATH line at the top of the script should fix this, but double-check ImageMagick is installed: brew install imagemagick
• Also confirm the shell in Automator is set to /bin/zsh

Test it in Terminal first

zsh /path/to/add_gradient_background.sh /path/to/image.jpg

This shows the exact error if something goes wrong.

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Output example

✅ Saved: /Users/you/Desktop/photo_gradient.jpg
   Gradient: #3A1F8C → #C04A22 | Angle: 135° | Shadow: offset=12px blur=18px